Orthopedic fixation control and visualization

ABSTRACT

A guided frame matching technique may be employed in which a graphical projection of a fixator is used to guide and assist a user in identifying fixator elements within an image. Upon being overlaid on an image, the graphical projection of fixator may be manipulated to align with, and overlay, fixator elements displayed within the image. Additionally, a three-dimensional overview of an imaging scene of the fixator may be generated. The three-dimensional overview may include a three-dimensional graphical model that displays representations of images of the fixator attached to anatomical structure segments as well as representations of imaging sources, reference locations, fixator elements, and anatomical structure segments. When the images are not truly orthogonal, a modified second image representation may be displayed to represent a second image that is truly orthogonal to a first image.

BACKGROUND

Techniques used to treat fractures and/or deformities of anatomical structures, such as bones, can include the use of external fixators, such as hexapods and other fixation frames, which are surgically mounted to anatomical structure segments on opposed sides of a fracture site. A pair of radiographic images is taken of the fixator and anatomical structure segments at the fracture site. Data from the images is then manipulated to construct a three-dimensional representation of the fixator and the anatomical structures segments that can be used in developing a treatment plan, which may for example comprise realigning the anatomical structure segments through adjustments to the fixator.

Existing techniques for controlling fixator manipulation may, however, involve a number of limitations that may introduce inefficiency, complication, and unreliability. For example, some conventional techniques may rely on a surgeon or other user to indicate locations of certain fixator elements, such as struts, within images that are displayed in a graphical user interface of a computer. However, it may often be difficult for the user to identify and mark positions of the struts and other fixator elements within the images. In particular, depending upon the location and orientation from which an image is captured, struts and other fixator elements may be not be identified easily, such as because they may wholly or partially overlap one another or may otherwise be obscured within the images. This may make it cumbersome for the user to identify the fixator elements, thereby increasing time required to identify the elements, increasing the probability of errors, and reducing the reliability of the calculations. As another example, some conventional techniques may be limited with respect to the ability to visualize a complete three-dimensional fixator imaging scene for the user. Additionally, when images are non-orthogonal, the user may be unable to efficiently view representations of various corrections, such as corrections to the anatomical structure angulations, calculated by the software corresponding to true orthogonal images. Thus, insufficient feedback may be provided to the user, thereby resulting in additional errors. This may reduce the reliability of the treatment plan, possibly resulting in improper alignment of anatomical structures segments during the healing process, compromised union between the anatomical structure segments, necessitating additional rounds of radiographic imaging to facilitate alignment corrections, or even necessitating additional surgical procedures.

SUMMARY

Techniques for orthopedic fixation control and visualization, for example for correction of a deformity of an anatomical structure, such as a bone, are described herein. In particular, in some examples, a fixation apparatus may be attached to first and second anatomical structure segments. Images, such as x-rays, of the fixation apparatus and the attached anatomical structure segments may then be captured from different orientations with respect to the fixation apparatus.

In some examples, various manipulations to the fixation apparatus for correction of the anatomical structure deformity may be determined based on positions and orientations of the anatomical structure segments in three-dimensional space. Also, in some examples, the positions and orientations of the anatomical structure segments in three-dimensional space may be determined based on the images. In particular, in some cases, the positions and orientations of the anatomical structure segments in three-dimensional space may be determined by having a surgeon or other user indicate locations of various fixator elements and anatomical structures within the images. However, as described above, it may often be difficult for the user to identify and mark positions of certain fixator elements, such as struts, within the images. In particular, depending upon the location and orientation from which an image is captured, struts and other fixator elements may be not be identified easily, such as because they may wholly or partially overlap one another or may otherwise be obscured within the images. For example, in some cases, it may often be more difficult to identify struts within a lateral image than to identify the struts within an anterior image, such as because the struts may often overlap one another when viewed within the lateral image. This may make it cumbersome for the user to identify the fixator elements, thereby increasing time required to identify the elements, increasing the probability of errors, and reducing the reliability of the calculations.

In some examples, to alleviate the above and other problems, a guided frame matching technique may be employed in which a graphical projection of the fixator is used to guide and assist the user in identifying fixator elements within an image. In particular, locations of fixator elements, such as rings and/or struts of the fixator, may be identified by a user within a first image, for example an anterior image or other image in which the fixator elements are easily identifiable. A graphical projection of the fixator, such as including graphical representations of the rings and/or struts, may then be generated based at least in part on the identified locations of the fixator elements in the first image. The graphical projection of the fixator may then be overlaid upon a second image, such as a lateral image or other image in which the fixator elements are not easily identifiable. The graphical projection of the fixator may then be used within the second image as a guide, such as to assist the user in identifying locations of the fixator elements within the second image. In some examples, the graphical projection of the fixator may be rotated relative to the locations of the fixator elements in the first image. In particular, the graphical projection of the fixator may be rotated based at least in part on an angle of image planes of the first and the second images with respect to one another. For example, if the first image is an anterior image, and the second image is a lateral image at an angle of ninety degrees to the anterior image, then the graphical projection of the fixator, upon being overlaid onto the second image, may be rotated ninety degrees relative to the identified locations of the fixator elements in the first image. The graphical projection of the fixator may also be modified within the second image by a user, for example by moving, resizing and/or further rotating the graphical projection of the fixator, such as to better align with the locations of the fixator elements in the second image. Upon being overlaid on the second image, the graphical projection of fixator may serve as a guide to assist the user in identifying fixator elements within the second image, such as by manipulating the graphical projection of the fixator to align with, and overlay, fixator elements displayed within the second image.

Another technique for improving accuracy and reliability of input values and resulting calculations is disclosed herein that provides a three-dimensional overview of an imaging scene of the fixator. The three-dimensional overview may be used to provide feedback and visual confirmation to help ensure that the calculated positions and orientations of anatomical structures is reliable and correct. In particular, the three-dimensional overview may include a three-dimensional graphical model that is displayed in a graphical user interface of a computing system. The three-dimensional graphical model may include a first image representation that represents a first image and may include a second image representation that represents a second image. The first image representation and the second image representation may be displayed at an angle that is the same as the angle between the image planes of the first and second images. The three-dimensional model may also include graphical representations of virtual locations corresponding to respective first and second imaging sources of the first and the second image. A first virtual line may connect a first virtual location corresponding to the first imaging source to a reference location on the first image representation. A second virtual line may connect a second virtual location corresponding to the second imaging source to the same reference location on the second image representation. In some examples, the reference location may be a reference point of the first or the second anatomical structure segment, such as an endpoint of the anatomical structure segment. The three-dimensional graphical model may display a first graphical representation associated with a shortest distance (e.g., intersection) between the first virtual line and the second virtual line, and this first graphical representation may represent a physical location of the reference location in three-dimensional space. The three-dimensional graphical model may also display graphical representations of fixator elements (rings, struts, etc.) at virtual locations that represent physical locations of the fixator elements in the three-dimensional space. The three-dimensional graphical model may also display graphical representations of the anatomical structure segments at virtual locations that represent physical locations of the anatomical structure segments in the three-dimensional space. The three-dimensional graphical model may be zoomed, panned, and rotated in any combination of one or more directions by a user.

In some examples, when the first and the second image planes are non-orthogonal, the three-dimensional graphical model may display a modified second image representation that is orthogonal to the first image representation. The modified second image representation may represent a modified second image having an image plane that is truly orthogonal to the image plane of the first image. In some examples, the software may calculate the angle of the anatomical structure segments that would be displayed in the second image if the second image were truly orthogonal to the first image. The software may then display, in the modified second image representation, a modified second image in which the anatomical structure segments are displayed with the calculated angle with respect to one another. In this way, the software may demonstrate to the user how measured anatomical structure deformity values from a second image that is not truly orthogonal to the first image may be adjusted to corrected anatomical structure deformity values for truly orthogonal images, and the software provide a guidance to validate the corrected values for use in the deformity calculations.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

The foregoing summary, as well as the following detailed description of the preferred embodiments of the application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the methods and/or techniques of orthopedic fixation with imagery analysis, there are shown in the drawings preferred embodiments. It should be understood, however, that the instant application is not limited to the precise arrangements and/or instrumentalities illustrated in the drawings, in which:

FIG. 1 is a perspective view of a fixation assembly positioned for imaging in accordance with an embodiment;

FIG. 2 is a perspective view of an example imaging process of the fixation assembly illustrated in FIG. 1;

FIGS. 3A and 3B are flow diagrams illustrating an example process for controlling manipulation of a fixation apparatus to correct an anatomical structure deformity;

FIG. 4 is a screen shot of an example interface for selecting a Perspective Frame Matching (PFM) technique;

FIG. 5 is a screen shot of an example configuration information entry interface for the PFM technique;

FIG. 6 is a screen shot of an example first image information entry interface for the PFM technique;

FIG. 7 is a screen shot of an example close-up assist interface for the PFM technique;

FIGS. 8A-8H are screen shots of an example second image information entry interface for the PFM technique;

FIG. 9 is a screen shot of example deformity parameter interface for the PFM technique;

FIG. 10 is a screen shot of an example mounting parameter interface for the PFM technique;

FIG. 11 is a screen shot of a first example treatment plan interface for the PFM technique;

FIG. 12 is a screen shot of a second example treatment plan interface for the PFM technique;

FIG. 13 is a screen shot of a third example treatment plan interface for the PFM technique;

FIG. 14 is a flow diagram illustrating an example process for providing a graphical projection of a fixator using a guided frame matching technique;

FIG. 15A is a diagram illustrating example images of first and second anatomical structure segments and a fixator attached thereto;

FIG. 15B is a diagram illustrating example first and second images of a fixator in which locations of fixator elements are indicated in the first image but not the second image;

FIG. 16 is a diagram illustrating example graphical projection of a fixator overlaid upon an image;

FIG. 17A is a diagram illustrating an example graphical projection of a fixator that is manipulated by a user;

FIG. 17B is a diagram illustrating example first and second images of a fixator in which locations of fixator elements are indicated in both the first image and the second image;

FIG. 18 is a flow diagram illustrating an example process for generating a three-dimensional overview of an imaging scene of a fixator;

FIG. 19 is a diagram illustrating an example three-dimensional graphical model of the imaging scene of the fixator;

FIG. 20 is a diagram illustrating an example three-dimensional graphical model including graphical representations of fixator rings;

FIG. 21 is a diagram illustrating an example three-dimensional graphical model including graphical representations of fixator struts and anatomical structure segments;

FIG. 22 is a diagram illustrating an example three-dimensional graphical model from an anteroposterior perspective;

FIG. 23 is a diagram illustrating an example three-dimensional graphical model from a lateral perspective;

FIG. 24 is a diagram illustrating an example rotated three-dimensional graphical model;

FIG. 25 is a diagram illustrating an example modified second image representation; and

FIG. 26 is a block diagram of an example computing device for use in accordance with the present disclosure.

DETAILED DESCRIPTION

For convenience, the same or equivalent elements in the various embodiments illustrated in the drawings have been identified with the same reference numerals. Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “top” and “bottom” designate directions in the drawings to which reference is made. The words “inward”, “inwardly”, “outward”, and “outwardly” refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. The terminology intended to be non-limiting includes the above-listed words, derivatives thereof and words of similar import.

Referring initially to FIG. 1, bodily tissues, for instance first and second anatomical structure segments 102, 104, can be aligned and/or oriented to promote union or other healing between the bodily tissues. Anatomical structures may include, for example, anatomical tissue and artificial anatomical implants. Anatomical tissue may include, for example, bone or other tissue in the body. The alignment and/or orientation of the bodily tissues can be achieved by connecting the bodily tissues to an adjustable fixation apparatus, such as orthopedic fixator 100. The orthopedic fixator can comprise an external fixation apparatus that includes a plurality of discrete fixator members that remain external to the patient's body, but that are attached to respective discreet bodily tissues, for example with minimally invasive attachment members. A fixation apparatus may include, for example, a distraction osteogenesis ring system, a hexapod, or a Taylor spatial frame. By adjusting the spatial positioning of the fixator members with respect to each other, the respective bodily tissues attached thereto can be reoriented and/or otherwise brought into alignment with each other, for example to promote union between the bodily tissues during the healing process. The use of external orthopedic fixators in combination with the imagery analysis and positioning techniques described herein can be advantageous in applications where direct measurement and manipulation of the bodily tissues is not possible, where limited or minimally invasive access to the bodily tissues is desired, or the like. Some examples of orthopedic fixators and their use for correcting deformities of anatomical structure segments, as well as techniques for performing imagery analysis on the fixators and anatomical structure segments are described in U.S. Pat. No. 9,642,649, entitled “ORTHOPEDIC FIXATION WITH IMAGERY ANALYSIS,” issued on May 9, 2017, the entirety of which is hereby incorporated by reference.

The fixator members can be connected to each other via adjustment members, the adjustment members configured to facilitate the spatial repositioning of the fixator members with respect to each other. For example, in the illustrated embodiment, the orthopedic fixator 100 comprises a pair of fixator members in the form of an upper fixator ring 106 and a lower fixator ring 108. The fixator rings 106, 108 can be constructed the same or differently. For instance, the fixator rings 106, 108 can have diameters that are the same or different. Similarly, the fixator rings 106, 108 can be constructed with varying cross sectional diameters, thicknesses, etc. It should be appreciated that the fixator members of the orthopedic fixator 100 are not limited to the illustrated upper and lower fixator rings 106, 108, and that the orthopedic fixator 100 can be alternatively constructed. For example, additional fixator rings can be provided and interconnected with the fixator ring 106 and/or 108. It should further be appreciated that the geometries of the fixator members are not limited to rings, and that at least one, such as all of the fixator members can be alternatively constructed using any other suitable geometry.

The first and second anatomical structure segments 102, 104 can be rigidly attached to the upper and lower fixator rings 106, 108, respectively, with attachment members that can be mounted to the fixator rings 106, 108. For example, in the illustrated embodiment, attachment members are provided in the form of attachment rods 110 and attachment wires 112.

The rods 110 and the wires 112 extend between proximal ends attached to mounting members 114 that are mounted to the fixator rings 106, 108, and opposed distal ends that are inserted into or otherwise secured to the anatomical structure segments 102, 104. The mounting members 114 can be removably mounted to the fixator rings 106, 108 at predefined points along the peripheries of the fixator rings 106, 108, for example by disposing them into threaded apertures defined by the fixator rings. With respect to each fixator ring 106, 108, the mounting members 114 can be mounted to the upper surface of the ring, the lower surface of the ring, or any combination thereof. It should be appreciated that the attachment members are not limited to the configuration of the illustrated embodiment. For example, any number of attachment members, such as the illustrated rods 110 and wires 112 and any others, can be used to secure the anatomical structure segments to respective fixator members as desired. It should further be appreciated that one or more of the attachment members, for instance the rods 110 and/or wires 112, can be alternatively configured to mount directly to the fixator rings 106, 108, without utilizing mounting members 114.

The upper and lower fixator rings 106, 108 can be connected to each other by at least one, such as a plurality of adjustment members. At least one, such as all, of the adjustment members can be configured to allow the spatial positioning of the fixator rings with respect to each other to be adjusted. For example, in the illustrated embodiment, the upper and lower fixator rings 106, 108 are connected to each other with a plurality of adjustment members provided in the form of adjustable length struts 116. It should be appreciated that the construction of the orthopedic fixator 100 is not limited to the six struts 116 of the illustrated embodiment, and that more or fewer struts can be used as desired.

Each of the adjustable length struts 116 can comprise opposed upper and lower strut arms 118, 120. Each of the upper and lower strut arms 118, 120 have proximal ends disposed in a coupling member, or sleeve 122, and opposed distal ends that are coupled to universal joints 124 mounted to the upper and lower fixator rings 106, 108, respectively. The universal joints of the illustrated embodiment are disposed in pairs spaced evenly around the peripheries of the upper and lower fixator rings 106, 108, but can be alternatively placed in any other locations on the fixator rings as desired.

The proximal ends of the upper and lower strut arms 118, 120 of each strut 116 can have threads defined thereon that are configured to be received by complementary threads defined in the sleeve 122, such that when the proximal ends of the upper and lower strut arms 118, 120 of a strut 116 are received in a respective sleeve 122, rotation of the sleeve 122 causes the upper and lower strut arms 118, 120 to translate within the sleeve 122, thus causing the strut 116 to be elongated or shortened, depending on the direction of rotation. Thus, the length of each strut 116 can be independently adjusted with respect to the remaining struts. It should be appreciated that the adjustment members are not limited to the length adjustable struts 116 of the illustrated embodiment, and that the adjustment members can be alternatively constructed as desired, for example using one or more alternative geometries, alternative length adjustment mechanisms, and the like.

The adjustable length struts 116 and the universal joints 124 by which they are mounted to the upper and lower fixator rings 106, 108, allow the orthopedic fixator 100 to function much like a Stewart platform, and more specifically like a distraction osteogenesis ring system, a hexapod, or a Taylor spatial frame. That is, by making length adjustments to the struts 116, the spatial positioning of the upper and lower fixator rings 106, 108, and thus the anatomical structure segments 102, 104 can be altered. For example, in the illustrated embodiment the first anatomical structure segment 102 is attached to the upper fixator ring 106 and the second anatomical structure segment 104 is attached to the lower fixator ring 108. It should be appreciated that attachment of the first and second anatomical structure segments 102, 104 to the upper and lower fixator rings 106, 108 is not limited to the illustrated embodiment (e.g., where the central longitudinal axes L1, L2 of the first and second anatomical structure segments 102, 104 are substantially perpendicular to the respective planes of the upper and lower fixator rings 106, 108), and that a surgeon has complete flexibility in aligning the first and second anatomical structure segments 102, 104 within the upper and lower fixator rings 106, 108 when configuring the orthopedic fixator 100.

By varying the length of one or more of the struts 116, the upper and lower fixator rings 106, 108, and thus the anatomical structure segments 102 and 104 can be repositioned with respect to each other such that their respective longitudinal axes L1, L2 are substantially aligned with each other, and such that their respective fractured ends 103, 105 abut each other, so as to promote union during the healing process. It should be appreciated that adjustment of the struts 116 is not limited to the length adjustments as described herein, and that the struts 116 can be differently adjusted as desired. It should further be appreciated that adjusting the positions of the fixator members is not limited to adjusting the lengths of the length adjustable struts 116, and that the positioning of the fixator members with respect to each other can be alternatively adjusted, for example in accordance the type and/or number of adjustment members connected to the fixation apparatus.

Repositioning of the fixator members of an orthopedic fixation apparatus, such as orthopedic fixator 100, can be used to correct displacements of angulation, translation, rotation, or any combination thereof, within bodily tissues. A fixation apparatus, such as orthopedic fixator 100, utilized with the techniques described herein, can correct a plurality of such displacement defects individually or simultaneously. However, it should be appreciated that the fixation apparatus is not limited to the illustrated orthopedic fixator 100, and that the fixation apparatus can be alternatively constructed as desired. For example, the fixation apparatus can include additional fixation members, can include fixation members having alternative geometries, can include more or fewer adjustment members, can include alternatively constructed adjustment members, or any combination thereof.

Referring now to FIG. 2, an example imaging of a fixation apparatus will now be described in detail. The images can be captured using the same or different imaging techniques. For example, the images can be acquired using x-ray imaging, computer tomography, magnetic resonance imaging, ultrasound, infrared imaging, photography, fluoroscopy, visual spectrum imaging, or any combination thereof.

The images can be captured from any position and/or orientation with respect to each other and with respect to the fixator 100 and the anatomical structure segments 102, 104. In other words, there is no requirement that the captured images be orthogonal with respect to each other or aligned with anatomical axes of the patient, thereby providing a surgeon with near complete flexibility in positioning the imagers 130. Preferably, the images 126, 128 are captured from different directions, or orientations, such that the images do not overlap. For example, in the illustrated embodiment, the image planes of the pair of images 126, 128 are not perpendicular with respect to each other. In other words, the angle α between the image planes of the images 126, 128 is not equal to 90 degrees, such that the images 126, 128 are non-orthogonal with respect to each other. Preferably, at least two images are taken, although capturing additional images may increase the accuracy of the method.

The images 126, 128 can be captured using one or more imaging sources, or imagers, for instance the x-ray imagers 130 and/or corresponding image capturing devices 127, 129. The images 126, 128 can be x-ray images captured by a single repositionable x-ray imager 130, or can be captured by separately positioned imagers 130. Preferably, the position of the image capturing devices 127, 129 and/or the imagers 130 with respect to the space origin 135 of the three-dimensional space, described in more detail below, are known. The imagers 130 can be manually positioned and/or oriented under the control of a surgeon, automatically positioned, for instance by a software assisted imager, or any combination thereof. The fixator 100 may also have a respective fixator origin 145.

Referring now to FIGS. 3A and 3B, an example process for controlling manipulation of a fixation apparatus including rings and struts to correct an anatomical structure deformity of first and second anatomical structure segments will now be described in detail. In particular, at operation 310, first and second anatomical structure segments are attached to a fixation apparatus, for example as shown in FIG. 1 and described in detail above. At operation, 312, first and second images of the fixation apparatus and the attached first and second anatomical structure segments are captured, for example as shown in FIG. 2 and described in detail above.

The remaining operations of the process of FIGS. 3A and 3B (e.g., operations 314-342) will now be described in association with a treatment technique referred to hereinafter as Perspective Frame Matching, in which images, such as post-operative x-rays, may be used along with a frame to generate deformity and mounting parameters for a strut adjustment plan. For example, referring now to FIG. 4, an example treatment planning technique selection interface 400-A is shown. In the example of FIG. 4, the user has selected option 401 in order to use the Perspective Frame Matching (PFM) technique, which will now be described in detail with reference to FIGS. 5-13.

Referring back to FIG. 3A, at operation 314, configuration information associated with a fixation apparatus is received, for example using one or more graphical user interfaces of a computing system. In some examples, the configuration information may include one or more geometric characteristics (e.g., size, length, diameter, etc.) of one or more elements of the fixation apparatus, such as struts, hinges, rings, and others. In some examples, the configuration information may include information such as ring types (e.g., full ring, foot plate, etc.), indications of mounting points (e.g., ring holes) used for strut mounting, and other information. In some examples, the configuration information may also include information about marker elements, for example that are mounted to components of the fixation apparatus, such as struts, hinges, and rings. Referring now to FIG. 5, an example configuration information entry interface 500 is shown. As shown, interface 500 includes ring type indicators 501 and 502, which, in this example, are drop down menus that may be used to select ring types for the proximal and distal rings, respectively. Indicators 501 and 502 are set to the “Full” option to indicate that the proximal and distal rings are full rings. Interface 500 also includes diameter indicators 503 and 504, which, in this example, are drop down menus that may be used to select diameters or lengths for the proximal and distal rings, respectively.

The interface 500 also includes controls for entry of strut information. In particular, interface 500 includes six drop down menus 512 may each be used to indicate a size of a respective strut. Global strut size indicator 511 may also be used to globally select a size for all six struts. Length selectors 513 may be each be used to select a length of a respective strut. Length indicators 514 may be each be used to provide a visual representation of the lengths of the respective struts. It is noted that the length indicators 514 do not necessarily depict the actual exact length of each strut, but rather represent the comparative lengths of the struts with respect to one another.

Save and Update button 516 may be selected to save and update the configuration information values shown in interface 500. In some examples, selection of button 516 may cause interface 500 to display and/or update a graphical representation 520 of the fixation apparatus generated based, at least in part, on the entered configuration information. The graphical representation 520 may be displayed using one or more graphical user interfaces of a computing system. As shown, graphical representation 520 includes six struts that may be color-coded in multiple colors for easy identification. For example, in some cases, each of the struts (or at least two of the struts) may be shown in different colors with respect to one another. The struts in graphical representation 520 may have sizes, lengths, mounting points, and other features corresponding to entered configuration information. Graphical representation 520 also depicts the fixator rings, which may have diameters/lengths, ring types, and other features corresponding to entered configuration information. Graphical representation 520 may, for example, improve efficiency and reliability by providing the user with a visual confirmation of information entered into interface 500, for example to allow fast and easy identification of errors or other problems.

At operation 316, images of the fixation apparatus and the first and second anatomical structure segments attached thereto are displayed, for example using one or more graphical user interfaces of a computing system. The displayed images may include images that were captured at operation 312, such as using x-ray imaging, computer tomography, magnetic resonance imaging, ultrasound, infrared imaging, photography, fluoroscopy, visual spectrum imaging, or any combination thereof. Techniques for acquiring images of the fixation apparatus and the first and second anatomical structure segments are described in detail above and are not repeated here. As set forth above, the acquired and displayed images need not necessarily be orthogonal to one another. Referring now to FIG. 6, an example first image information entry interface 600 is shown. As shown, interface 600 includes images 601-A and 601-B, which show the fixation apparatus and first and second anatomical structure segments from different angles. In the example of FIG. 6, image 601-A corresponds to an anteroposterior (AP) View, while image 601-B corresponds to a lateral (LAT) view. In some examples, the displayed images 601-A-B may be loaded and saved in computer memory, for example in a library, database or other local collection of stored images. The displayed images 601-A-B may then be selected and retrieved, acquired, and/or received from memory for display.

At operation 318, first image information is received, for example using one or more graphical user interfaces of a computing system. The first image information may include indications of one or more locations, within the images, of at least part of one or more elements of the fixation apparatus. For example, the first image information may include one or more indications of locations of struts, hinges, rings, and other fixator elements. In some examples, the first image information may also include information about locations, within the images, of marker elements, for example that are mounted to components of the fixation apparatus, such as struts, hinges, and rings. In some cases, the first image information may include points representing locations of hinges and/or lines or vectors representing locations of struts. In some examples, the first image information may be entered into a computing system by selecting or indicating one or more locations within the displayed images, for example using a mouse, keyboard, touchscreen or other user input devices. In particular, using one or more input devices, a user may select points or other locations in the images, draw lines, circles, and generate other graphical indications within the images. For example, in some cases, a user may generate a point or small circle at a particular location in an image to indicate a location (e.g., center point) of a hinge within the image. As another example, in some cases, a user may generate a line and/or vector within an image to indicate a location and/or length of a strut within the image.

For example, as shown in FIG. 6, interface 600 includes six AP View strut indicator buttons 611-A corresponding to each of the six struts of the fixation apparatus shown in AP View image 601-A. Each button 611-A includes text indicating a respective strut number (i.e., Strut 1, Strut 2, Strut 3, Strut 4, Strut 5, Strut 6). Buttons 611-A may be selected by a user to indicate a strut for which first image information (e.g., hinge locations, strut locations, etc.) will be provided by the user in AP View image 601-A. For example, in some cases, to provide first image information for Strut 1 in AP View image 601-A, a user may first select the top strut indicator button 611-A (labeled with the text “Strut 1”) in order to indicate to the software that the user is about to provide first image information for Strut 1 within AP View image 601-A. In some cases, the strut indicator button 611-A for Strut 1 may be pre-selected automatically for the user. Upon selection (or automatic pre-selection) of the strut indicator button 611-A for Strut 1, the user may proceed to draw (or otherwise indicate) a representation of Strut 1 within AP View image 601-A. For example, in some cases, the user may use a mouse or other input device to select a location 621 (e.g., a center point) of a proximal hinge for Strut 1 within image 601-A. In some examples, the user may then use a mouse or other input device to select a location 622 (e.g., a center point) of the distal hinge of Strut 1 within image 601-A. In some examples, the user may indicate the location and/or length of Strut 1 by selecting the locations of the proximal and distal hinges and/or as the endpoints of a line or vector that represents the location and/or length of Strut 1. For example, as shown in FIG. 6, the software may generate points or circles at the locations 621 and 622 of the proximal and distal hinges selected by the user within image 601-A. Additionally, the software may generate a line 623 representing the location and/or length of Strut 1 that connects the points or circles at the locations 621 and 622 and of the proximal and distal hinges selected by the user within image 601-A. Any other appropriate input techniques may also be employed by the user to indicate a location and/or length of Strut 1 within image 610-A, such as generating line 623 by dragging and dropping a mouse, using a finger and/or pen on a touch screen, keyboard, and others. In some examples, the above described process may be repeated to draw points representing proximal and distal hinges and lines representing the locations and/or lengths of each of the six struts in the AP View image 601-A. Furthermore, the above described process may also be repeated using LAT View strut indicator buttons 611-B to draw points representing proximal and distal hinges and lines representing the locations and/or lengths of each of the six struts in the LAT View image 601-B.

In some examples, the first image information generated within images 601-A and 601-B may include color-coded graphical representations of the struts, for example to enable the graphical representations to be more clearly associated with their respective struts. For example, in FIG. 6, the graphical representations (e.g., points, circles, and/or lines) of Strut 1 in images 601A- and 601-B may be colored in red. This may match a strut icon (which may also be colored red) displayed in the strut indicator buttons 611-A and 611-B for Strut 1 (displayed to the right of the text “Strut 1” in buttons 611-A and 611-B). As another example, in FIG. 6, the graphical representations (e.g., points, circles, and/or lines) of Strut 3 in images 601-A and 601-B may be colored in yellow. This may match a strut icon (which may also be colored yellow) displayed in the strut indicator buttons 611-A and 611-B for Strut 3 (displayed to the right of the text “Strut 3” in buttons 611-A and 611-B).

FIG. 6 includes an AP View close-up assist checkbox 616-A and a LAT View close-up assist checkbox 616-B, for example provided using one or more graphical interfaces of a computing system. Selection of checkboxes 616-A and 616-B may allow close-up views of areas of images 601-A and 601-B surrounding the proximal and distal hinges of the struts that are currently being drawn by the user. This may enable more accurate indications of the locations (e.g., center points) of the hinges. Referring now to FIG. 7, close-up assist interface 700 depicts another AP View image 701 with the close-up assist being selected to provide a proximal hinge close-up assist view 702 and a distal hinge close-up assist view 703. As shown, proximal hinge close-up assist view 702 provides an enlarged view of an area of AP View image 701 associated with the proximal hinge, while distal hinge close-up assist view 703 provides an enlarged view of an area of AP View image 701 associated with the distal hinge. The user may manipulate (e.g., drag and drop) the location of the point/circle 721 in proximal hinge close-up assist view 702 in order to more accurately depict the center point of the proximal hinge. The user may also manipulate (e.g., drag and drop) the location of the point/circle 722 in distal hinge close-up assist view 703 in order to more accurately depict the center point of the distal hinge. As should be appreciated, corresponding close-up assist views similar to views 702 and 703 may also be provided for a respective LAT View image, for example using one or more graphical interfaces of a computing system.

Referring back to FIG. 6, to the right of buttons 611-A, are six proximal hinge selector buttons 612-A. Additionally, to the right of buttons 612-A, are six distal hinge selector buttons 613-A. Furthermore, to the right of buttons 613-A, are six strut line selector buttons 614-A. In some examples, buttons 612-A and/or 613-A may be selected to use the locations (e.g., center points) of the proximal and/or distal hinges indicated in AP View image 601-A in calculating positions and orientations of the first and the second anatomical structure segments and rings of the fixation apparatus in three-dimensional space (see operation 322). Additionally, in some examples, buttons 612-A and/or 613-A may be selected to use the lines or vectors representing the location and/or length of struts indicated in AP View image 601-A in calculating positions and orientations of the first and the second anatomical structure segments in three-dimensional space. Similarly, buttons 612-B, 613-B, and 614-B may be used to select the use of locations (e.g., center points) of the proximal and/or distal hinges or strut lines or vectors indicated in LAT View image 601-B in calculating positions and orientations of the first and the second anatomical structure segments in three-dimensional space.

Referring again to FIG. 3A, at operation 320, second image information is received, for example using one or more graphical user interfaces of a computing system. The second image information may include indications of one or more locations, within the images, of at least part of the first and the second anatomical structure segments. In some examples, the second image information may include indications of center lines of the first and the second anatomical structure segments and/or one or more reference points (e.g., end points) of the first and the second anatomical structure segments. In some examples, the second image information may also include indications of locations of marker elements, for example implanted or otherwise associated with the first and the second anatomical structure segments. In some examples, the second image information may be entered into a computing system by selecting or indicating one or more locations within the displayed images, for example using a mouse, keyboard, touchscreen or other user input devices. In particular, using one or more input devices, a user may select points or other locations in the images, draw lines, circles, and generate other graphical indications within the images. For example, in some cases, a user may generate points or small circles at particular locations in an image to indicate one or more reference points (e.g., end points) of the first and the second anatomical structure segments within the images. As another example, in some cases, a user may generate a line within an image to indicate a center line of the first and the second anatomical structure segments within the images.

Referring now to FIG. 8A, an example second image information entry interface 800 is shown. As shown, interface 800 includes AP View image 601-A and LAT View image 601-B. Additionally, interface 800 includes buttons 801-808, which may be used to assist in indication of anatomical structure center lines and reference points as will be described below. In particular, buttons 801 and 805 may be selected to indicate a proximal anatomical structure reference point in the AP View and LAT View, respectively. Buttons 802 and 806 may be selected to indicate a distal anatomical structure reference point in the AP View and LAT View, respectively. Buttons 803 and 807 may be selected to indicate a proximal anatomical structure center line in the AP View and LAT View, respectively. Buttons 804 and 808 may be selected to indicate a distal anatomical structure center line in the AP View and LAT View, respectively. For example, as shown in FIG. 8A, a user may select button 807 and then use one or more input devices to draw the center line 831 for the proximal anatomical structure within LAT View image 601-B. In some examples, the center line 831 may be colored red. Additionally, two guidelines 832 are generated and displayed by the software on both sides of the red center line. In some examples, the guidelines 832 may be colored green. These guidelines 832 may be displayed while the user is drawing the center line 831 in order to assist the user in locating the center of the anatomical structure segment. The guidelines 832 may be generated at equal distances from each side of the center line 831 and may assist the user by, for example, potentially allowing the user to match (or nearly match) the guidelines 832 to sides of the anatomical structure segment. As shown in FIG. 8B, the user may select button 808 and then use one or more input devices to draw the center line 841 for the distal anatomical structure within LAT View image 601-B. As shown in FIG. 8C, the user may select button 803 and then use one or more input devices to draw the center line 851 for the proximal anatomical structure within AP View image 601-A. As shown in FIG. 8D, the user may select button 804 and then use one or more input devices to draw the center line 861 for the distal anatomical structure within AP View image 601-A. As shown in FIGS. 8B-8D, guidelines 832 may also be displayed for assistance in drawing center lines 841, 851 and 861.

As shown in FIG. 8E, the user may select button 805 and then use one or more input devices to indicate a reference point (e.g., end point) for the proximal anatomical structure within LAT View image 601-B. As shown, a user has indicated a reference point 811 in LAT View image 601-B at an end point of the proximal anatomical structure segment. Additionally, upon indication of reference point 811, the software may generate and display a corresponding dashed reference line 812 in AP View image 601-A. The reference line 812 is a line drawn across AP View image 601-A that passes through the location of the LAT View proximal reference point 811 within AP View image 601-A. The reference line 812 may, therefore, assist the user in determining the location of the corresponding AP View proximal reference point, which may often be at the intersection of the reference line 812 and the AP View proximal center line 851 within the AP View image 601-A. As shown in FIG. 8F, the user may select button 801 and then use one or more input devices to indicate a reference point (e.g., end point) for the proximal anatomical structure within AP View image 601-A. In this example, the AP View proximal anatomical structure reference point 814 is indicated at the intersection of reference line 812 and the AP View proximal center line 851 within the AP View image 601-A. The software may then generate and display a corresponding dashed reference line 813 in the LAT View image 601-B. The reference line 813 is a line drawn across LAT View image 601-B that passes through the location of the AP View proximal reference point 814 within LAT View image 601-B. The reference line 813 may assist the user by helping the user to confirm that the AP View reference point 814 was placed correctly by showing how well it lines up relative to the LAT View reference point 811.

As shown in FIG. 8G, the user may select button 806 and then use one or more input devices to indicate a reference point (e.g., end point) for the distal anatomical structure within LAT View image 601-B. As shown, a user has indicated a reference point 815 in LAT View image 601-B at an end point of the distal anatomical structure segment. Additionally, upon indication of reference point 815, the software may generate and display a corresponding dashed reference line 816 in AP View image 601-A. The reference line 816 is a line drawn across AP View image 601-A that passes through the location of the LAT View distal reference point 815 within AP View image 601-A. The reference line 816 may, therefore, assist the user in determining the location of the corresponding AP View distal reference point, which may often be at the intersection of the reference line 816 and the AP View distal center line within the AP View image 601-A. As shown in FIG. 8H, the user may select button 802 and then use one or more input devices to indicate a reference point (e.g., end point) for the distal anatomical structure within AP View image 601-A. In this example, the AP View distal anatomical structure reference point 817 is indicated at the intersection of reference line 816 and the AP View distal center line within the AP View image 601-A. The software may then generate and display a corresponding dashed reference line 818 in the LAT View image 601-B. The reference line 818 is a line drawn across LAT View image 601-B that passes through the location of the AP View distal reference point 817 within LAT View image 601-B. The reference line 818 may assist the user by helping the user to confirm that the AP View reference point 817 was placed correctly by showing how well it lines up relative to the LAT View reference point 815.

Referring again to FIG. 3A, at operation 322, positions and orientations of the first and second anatomical structure segments and rings of the fixation apparatus are determined in three-dimensional space. For example, in some cases, imaging scene parameters pertaining to fixator 100, the anatomical structure segments 102, 104, imager(s) 130, and image capturing devices 127, 129 are obtained. The imaging scene parameters can be used in constructing a three-dimensional representation of the positioning of the anatomical structure segments 102, 104 in the fixator 100, as described in more detail below. One or more of the imaging scene parameters may be known. Imaging scene parameters that are not known can be obtained, for example by mathematically comparing the locations of fixator element representations in the two-dimensional space of the x-ray images 126, 128 to the three-dimensional locations of those elements on the geometry of the fixator 100. In a preferred embodiment, imaging scene parameters can be calculated using a pin hole or perspective camera models. For example, the imaging scene parameters can be determined numerically using matrix algebra, as described in more detail below.

The imaging scene parameters can include, but are not limited to image pixel scale factors, image pixel aspect ratio, the image sensor skew factor, the image size, the focal length, the position and orientation of the imaging source, the position of the principle point (defined as the point in the plane of a respective image 126, 128 that is closest to the respective imager 130), positions and orientations of elements of the fixator 100, the position and orientation of a respective image receiver, and the position and orientation of the imaging source's lens.

In a preferred embodiment, at least some, such as all of the imaging scene parameters can be obtained by comparing the locations of representations of particular components, or fixator elements of the fixator 100 within the two-dimensional spaces of the images 126, 128, with the corresponding locations of those same fixator elements in actual, three-dimensional space. The fixator elements comprise components of the orthopedic fixator 100, and preferably are components that are easy to identify in the images 126, 128. Points, lines, conics, or the like, or any combination thereof can be used to describe the respective geometries of the fixator elements. For example, the representations of fixator elements used in the comparison could include center lines of one or more of the adjustable length struts 116, center points of the universal joints 124, center points of the mounting members 114, and the like.

The fixator elements can further include marker elements that are distinct from the above-described components of the fixator 100. The marker elements can be used in the comparison, as a supplement to or in lieu of using components of the fixator 100. The marker elements can be mounted to specific locations of components of the fixator 100 prior to imaging, can be imbedded within components of the fixator 100, or any combination thereof. The marker elements can be configured for enhanced viewability in the images 126, 128 when compared to the viewability of the other components of the fixator 100. For example, the marker elements may be constructed of a different material, such as a radio-opaque material, or may be constructed with geometries that readily distinguish them from other components of the fixator 100 in the images 126, 128. In an example embodiment, the marker elements can have designated geometries that correspond to their respective locations on the fixator 100.

Fixator elements can be identified for use in the comparison. For example, locations, within the images 126, 128 of fixator elements may be indicated using the first image information received at operation 318 and described in detail above. In some examples, the locations of the fixator elements in the two-dimensional space of the images 126, 128 may be determined with respect to local origins 125 defined in the imaging planes of the images 126, 128. The local origins 125 serve as a “zero points” for determining the locations of the fixator elements in the images 126, 128. The locations of the fixator elements can be defined by their respective x and y coordinates with respect to a respective local origin 125. The location of the local origin 125 within the respective image can be arbitrary so long it is in the plane of the image. Typically, the origin is located at the center of the image or at a corner of the image, such as the lower left hand corner. It should be appreciated that the locations of the local origins are not limited to illustrated local origins 125, and that the local origins 125 can be alternatively defined at any other locations.

In some examples, a respective transformation matrix P may then be computed for each of the images 126, 128. The transformation matrices can be utilized to map location coordinates of one or more respective fixator elements in actual three-dimensional space to corresponding location coordinates of the fixator element(s) in the two-dimensional space of the respective image 126, 128. It should be appreciated that the same fixator element(s) need not be used in the comparisons of both images 126, 128. For example, a fixator element used in constructing the transformation matrix associated with image 126 can be the same or different from the fixator element used in constructing the transformation matrix associated with image 128. It should further be appreciated that increasing the number of fixator elements used in computing the transformation matrices can increase the accuracy method. The following equation represents this operation:

$\begin{matrix} {\begin{bmatrix} x \\ y \\ 1 \end{bmatrix} = {P \cdot \begin{bmatrix} X \\ Y \\ Z \\ 1 \end{bmatrix}}} & (1) \end{matrix}$

The symbols x and y represent location coordinates, with respect to the local origin 125, of a fixator element point in the two-dimensional space of images 126, 128. The symbols X, Y and Z represent corresponding location coordinates, with respect to a space origin 135, of the fixator element point in actual three-dimensional space. In the illustrated embodiment, the point corresponding to the center of the plane defined by the upper surface of the upper fixator ring 106 has been designated as the space origin 135. The illustrated matrix P can be at least four elements wide and three elements tall. In a preferred embodiment, the elements of the matrix P can be computed by solving the following matrix equation: A·p=B  (2)

The vector p can contain eleven elements representing values of the matrix P. The following equations present arrangements of the elements in the vector p and the matrix P:

$\begin{matrix} {p = \begin{bmatrix} p_{1} & p_{2} & p_{3} & p_{4} & p_{5} & p_{6} & p_{7} & p_{8} & p_{9} & p_{10} & p_{11} \end{bmatrix}^{T}} & (3) \\ {P = \begin{bmatrix} p_{1} & p_{2} & p_{3} & p_{4} \\ p_{5} & p_{6} & p_{7} & p_{8} \\ p_{9} & p_{10} & p_{11} & p_{12} \end{bmatrix}} & (4) \end{matrix}$

In the preferred embodiment, the twelfth element p₁₂ of the matrix P can be set to a numerical value of one. The matrices A and B can be assembled using the two-dimensional and three-dimensional information of the fixator elements. For every point representing a respective fixator element, two rows of matrices A and B can be constructed. The following equation presents the values of the two rows added to the matrices A and B for every point of a fixator element (e.g., a center point of a respective universal joint 124):

$\begin{matrix} {{\begin{bmatrix} \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots \\ X & Y & Z & 1 & 0 & 0 & 0 & 0 & {{- x} \cdot X} & {{- x} \cdot Y} & {{- x} \cdot Z} \\ 0 & 0 & 0 & 0 & X & Y & Z & 1 & {{- y} \cdot X} & {{- y} \cdot Y} & {{- y} \cdot Z} \\ \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots \end{bmatrix} \cdot p} = \begin{bmatrix} \ldots \\ x \\ y \\ \ldots \end{bmatrix}} & (5) \end{matrix}$

The symbols X, Y and Z represent location coordinate values of a fixator element point in actual three-dimensional space relative to the space origin 135, and the symbols x and y represent location coordinate values of the corresponding fixator element point in the two-dimensional space of the respective image 126, 128 relative to local origin 125.

For every line representing a respective fixator element, two rows of matrices A and B can be constructed. The following equation presents the values of the two rows added to the matrices A and B for every line of a fixator element (e.g., a center line of a respective adjustable length strut 116):

$\begin{matrix} {{\begin{bmatrix} \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots \\ {X \cdot a} & {Y \cdot a} & {Z \cdot a} & a & {X \cdot b} & {Y \cdot b} & {Z \cdot b} & b & {X \cdot c} & {Y \cdot c} & {Z \cdot c} \\ {{dX} \cdot a} & {{dY} \cdot a} & {{dZ} \cdot a} & 0 & {{dX} \cdot b} & {{dY} \cdot b} & {{dZ} \cdot b} & 0 & {{dY} \cdot c} & {{dY} \cdot c} & {{dZ} \cdot c} \\ \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots & \ldots \end{bmatrix} \cdot p} = \begin{bmatrix} \ldots \\ {- c} \\ 0 \\ \ldots \end{bmatrix}} & (6) \end{matrix}$

The symbols X, Y and Z represent location coordinate values of a point belonging to a line of a fixator element in actual three-dimensional space relative to the space origin 135. The symbols dX, dY and dZ represent gradient values of the line in actual three-dimensional space. The symbols a, b and c represent constants defining a line in the two-dimensional space of a respective image 126, 128. For example, a, b, and c can be computed using two points belonging to a line on a respective image 126, 128. In a preferred embodiment, the value of b is assumed to be 1, unless the line is a vertical line, in which case the value of b is zero. A correlation of constants a, b and c with the respective image coordinates x and y is presented in the following equation: a·x+b·y+c=0  (7)

The equation (2) can be over constrained by using six or more fixator elements, for example the adjustable length struts 116. It should be appreciated that it is not necessary for all of the fixator elements to be visible in a single one of the images 126, 128 in order to obtain the matrix P. It should further be appreciated that if one or more of the above-described imaging scene parameters are known, the known parameters can be used to reduce the minimum number of the fixator elements required to constrain equation (2). For instance, such information could be obtained from modern imaging systems in DICOM image headers. Preferably, a singular value decomposition or least squares method can be used to solve equation (2) for values of the vector p.

In some examples, the transformation matrices may then be decomposed into imaging scene parameters. The following equation can be used to relate the matrix P to matrices E and I: P=I·E  (8)

It should be appreciated that additional terms can be introduced when decomposing the matrix P. For example, the method presented by Tsai, described in “A Versatile Camera Calibration Technique for High-Accuracy 3D Machine Vision Metrology Using of-the-shelf TV Cameras and Lenses”, IEEE Journal of Robotics & Automation, RA-3, No. 4, 323-344, August 1987, which is incorporated herein by reference in its entirety, can be used to correct images 126, 128, for radial distortion.

Matrices E and I contain imaging scene parameters. The following equation represents a composition of the matrix I:

$\begin{matrix} {I = \begin{bmatrix} {sx} & 0 & {- {tx}} \\ 0 & {sy} & {{- t}y} \\ 0 & 0 & {1/f} \end{bmatrix}} & (9) \end{matrix}$

The symbols sx and sy represent values of image coordinate scale factors (e.g., pixel scale factors). The symbol f, representing the focal length, corresponds to the value of the shortest distance between a respective imaging source 130 and the plane of a corresponding image 126, 128. The symbols tx and ty represent the coordinates of the principle point relative to the local origin 125 of the respective image 126, 128. The following equation represents the composition of the matrix E:

$\begin{matrix} {E = \begin{bmatrix} r_{1} & r_{2} & r_{3} & {- \left( {{r_{1} \cdot o_{x}} + {r_{2} \cdot o_{y}} + {r_{3} \cdot o_{z}}} \right)} \\ r_{4} & r_{5} & r_{6} & {- \left( {{r_{4} \cdot o_{x}} + {r_{5} \cdot o_{y}} + {r_{6} \cdot o_{z}}} \right)} \\ r_{7} & r_{8} & r_{9} & {- \left( {{r_{7} \cdot o_{x}} + {r_{8} \cdot o_{y}} + {r_{9} \cdot o_{z}}} \right)} \end{bmatrix}} & (10) \end{matrix}$

The symbols o_(x), o_(y) and o_(z) represent values of the position of the fixator 100 in actual three-dimensional space. The symbols r₁ to r₉ describe the orientation of the fixator 100. These values can be assembled into a three-dimensional rotational matrix R represented by the following equation:

$\begin{matrix} {R = \begin{bmatrix} r_{1} & r_{2} & r_{3} \\ r_{4} & r_{5} & r_{6} \\ r_{7} & r_{8} & r_{9} \end{bmatrix}} & (11) \end{matrix}$

The methods of Trucco and Verri, as described in “Introductory Techniques of 3-D Computer Vision”, Prentice Hall, 1998, or the method of Hartley, as described in “Euclidian Reconstruction from Uncalibrated Views”, Applications of Invariance in Computer Vision, pages 237-256, Springer Verlag, Berlin Heidelberg, 1994, which are incorporated herein in their entireties, can be used to obtain values of the matrices E and/or I. Utilizing the resulting values of matrices E and I, a complete three-dimensional imaging scene of the fixator 100 and the anatomical structure segments 102, 104 can be reconstructed.

For example, FIG. 2 illustrates an example three-dimensional imaging scene reconstructed from the x-ray images 126, 128. In the illustrated embodiment, x-rays are emitted from x-ray imagers 130. It should be appreciated that the x-ray imagers 130 can be the same or different imagers, as described above. The x-rays emitted from the imagers 130 are received on by corresponding imaging devices, thus capturing the images 126, 128. Preferably, the positioning of the imagers 130 with respect to the local origins 125 is known.

In some examples, the images 126, 128 and the imaging scene parameters may then be used to obtain the positions and/or orientations of the anatomical structure segments 102, 104 in three-dimensional space. The position and/or orientation data obtained can be used to develop a treatment plan for a patient, for example to change the orientation and/or position of the fractured first and second anatomical structure segments 102, 104 in order to promote union between the anatomical structure segments 102, 104, as described in more detail below. It should be appreciated that the methods and techniques described herein are not limited to applications of repositioning broken anatomical structures, and that orthopedic fixation with imagery analysis can be used in any other type of fixation procedure as desired, for example lengthening of anatomical structures, correction of anatomical defects, and the like.

In some examples, anatomical structure elements comprising representations of particular portions (e.g., anatomical features) of the anatomical structure segments 102, 104, may then be identified and their locations within the images 126, 128 determined. For example, locations, within the images 126, 128 of the first and the second anatomical structure segments may be indicated using the second image information received at operation 320 and described in detail above. In some examples, the locations of the anatomical structure elements may be determined with respect to the respective local origins 125 of images 126, 128.

The anatomical structure elements can be used in the construction of the three-dimensional representation of the position and/or orientation of the anatomical structure segments 102, 104. Preferably, the anatomical structure elements are easy to identify in the images 126, 128. Points, lines, conics, or the like, or any combination thereof can be used to describe the respective geometries of the anatomical structure elements. For example, in the illustrated embodiment, points 134 and 136 representing the fractured ends 103, 105 of the anatomical structure segments 102, 104, respectively, are identified as anatomical structure elements in the images 126, 128.

The anatomical structure elements can further include marker elements that are implanted into the anatomical structure segments 102, 104 prior to imaging. The marker elements can be used as a supplement to or in lieu of the above-described anatomical structure elements identified in the images 126, 128. The marker elements can be configured for enhanced viewability in the images 126, 128 when compared to the viewability of anatomical features of the anatomical structure segments 102, 104. For example, the marker elements may be constructed of a radio-opaque material, or may be constructed with readily distinguishable geometries.

A three-dimensional representation 200 of the anatomical structure segments 102, 104 can be reconstructed. The three-dimensional representation can be constructed with or without a corresponding representation of the fixator 100. In the illustrated embodiment, pairs of ray-lines, such as ray lines 138, 140 and 142, 144 can be constructed for the anatomical structure element points 134, 136, respectively. Each ray line connects an anatomical structure element in one of the images 126, 128 with a respective imager 130. Each pair of ray lines can be analyzed for a common intersection point, such as points 146, 148. The common intersection points 146, 148 represent the respective positions of the anatomical structure element points 134, 136, in the three-dimensional representation of the anatomical structure segments 102, 104. Of course more than a pair of ray lines, such as a plurality, can be constructed, for example if more than two images were captured. If the ray lines of a particular set do not intersect, a point closest to all the ray lines in the set can be used as the common intersection point.

The positions and/or orientations of the anatomical structure segments 102, 104 can be quantified or measured using common intersection points, for instance points 146, 148. For example, lines representing center lines of the anatomical structure segments 102, 104 can be constructed and can be compared to the anatomical axes of the patient. Additionally, the distance between the fractured ends 103, 105 of the anatomical structure segments 102, 104 can be quantified. Using these or similar techniques, the positions and/or orientations of the anatomical structure segments 102, 104 can be determined. It is further noted that, in some examples, in addition to the positions and orientations of the first and second anatomical structure segments, the positions and orientation of rings (and/or other elements of the fixation apparatus) in three-dimensional space may also be determined, for example using any of the techniques described. For example, in some cases, locations of the rings within the images 126, 128 may be determined based on the first image information and/or other provided information. In some examples, these locations may then be used to determine the positions and orientations of the rings in three-dimensional space. Additionally, in some examples, configuration information for the fixation apparatus, such as ring diameters and strut length and mounting information, may also be used to determine positions and orientations of the rings in three-dimensional space.

Referring now to FIG. 3B, at operation 324, one or more deformity parameters are calculated. The deformity parameters may include parameters relating to the deformity associated with the first and second anatomical structure segments. For example, in some cases, the deformity parameters may include an amount of translation (e.g., lateral, medial, anterior, and/or posterior), a degree of coronal angulation (e.g., valgus and/or varus), a degree of sagittal angulation, an amount by which anatomical structure length is too short and/or too long, a degree of clinical rotational deformity (e.g., internal and/or external), and others. In some examples, the deformity parameters may be calculated as part of the process determining the positions and orientations of the first and segment anatomical structure segments described above at operation 422, for example using the techniques described above with reference to operation 422.

At operation 326, the deformity parameters calculated at operation 424 are displayed, for example using one or more graphical user interfaces of a computing system. Referring now to FIG. 9, a deformity parameter interface 900 is shown. As shown, interface 900 includes various fields 901-906 for displaying calculated values of various example deformity parameters, including AP View translation and coronal angulation, LAT View translation and sagittal angulation, an amount by which anatomical structure length is too short or too long, and a degree of clinical rotational deformity. In the example of FIG. 9, fields 901-905 each have a respective PFM badge 915 (including the text “PFM”) that is displayed to the left of each field 901-905. Each PFM badge 915 indicates that the value shown in the respective field 901-905 has been calculated by the software. Interface 900 allows the deformity parameter values that are displayed in each field 901-906 to be edited by a user, for example by typing a number in the fields 901-906 and/or by using number increment controls 916 displayed to the right of each field 901-906. When a user edits a value that was calculated by the software, the PFM badge 915 adjacent to the respective field may be removed to indicate that the value for the field has been edited by the user. In some examples, after editing the values in one or more fields, the user may select Refresh Perspective Frame Matching Data button 920 to return each of the fields to the value that was calculated by the software. Also, in some examples, after editing the values in one or more fields, the user may select Save and Update button 921 to cause the deformity parameters to be recalculated based on the edited values provided by the user, for example by repeating all or any portion of the calculations performed at operation 322.

At operation 328, a graphical representation of the position and orientation of the first and the second anatomical structure segments is generated and displayed. The graphical representation of the position and orientation of the first and the second anatomical structure segments may be displayed using one or more graphical user interfaces of a computing system. For example, as shown in FIG. 9, interface 900 includes a graphical representation 950 of the position and orientation of the first and the second anatomical structure segments. Graphical representation 950 includes a representation 931 of the proximal anatomical structure segment and a representation 932 of the distal anatomical structure segment. In some examples, the graphical representation 950 may be generated based, at least in part, on the positions and orientations of the first and segment anatomical structure segments determined at operation 322. In some examples, when the user edits one or more deformity parameters and selects Save and Update button 921, the graphical representation 950 may also be adjusted to reflect the saved edits to the deformity parameters. Graphical representation 950 may, for example, improve efficiency and reliability by providing the user with a visual confirmation of information entered into interface 900, for example to allow fast and easy identification of errors or other problems.

At operation 330, one or more mounting parameters are calculated. The mounting parameters may include parameters relating to mounting of a reference ring of the fixator onto a respective anatomical structure segment. For example, in some cases, the mounting parameters may include an amount of offset (e.g., lateral, medial, anterior, and/or posterior) such as for a center of the reference ring with respect to a reference point, a degree of tilt (e.g., proximal and/or distal), an amount of axial offset, a master tab rotation, and others. In some examples, the mounting parameters may be calculated as part of the process determining the positions and orientations of the first and segment anatomical structure segments described above at operation 322, for example using the techniques described above with reference to operation 322. It is noted that, for the process of FIG. 3, the reference ring is not necessarily required to be orthogonal with respect to the respective anatomical structure segment on which it is mounted. Thus, in some examples, the reference ring may be non-orthogonal with respect to the respective anatomical structure segment on which it is mounted.

At operation 432, the mounting parameters calculated at operation 430 are displayed, for example using one or more graphical user interfaces of a computing system. Referring now to FIG. 10, a mounting parameter interface 1000 is shown. As shown, interface 1000 includes various fields 1001-1006 for displaying calculated values of various example mounting parameters, including AP View offset and tilt, LAT View offset and tilt, axial offset, and master tab rotation. In the example of FIG. 10, fields 1001-1006 each have a respective PFM badge 1015 that is displayed to the left of each field 1001-1006. Each PFM badge 1015 indicates that the value shown in the respective field 1001-1006 has been calculated by the software. Interface 1000 allows the mounting parameter values that are displayed in each field 1001-1006 to be edited by a user, for example by typing a number in the fields 1001-1006 and/or by using number increment controls 1016 displayed to the right of each field 1001-1006. When a user edits a value that was calculated by the software, the PFM badge 1015 adjacent to the respective field may be removed to indicate that the value for the field has been edited by the user. In some examples, after editing the values in one or more fields, the user may select Refresh Perspective Frame Matching Data button 1020 to return each of the fields to the value that was calculated by the software. Also, in some examples, after editing the values in one or more fields, the user may select Save and Update button 1021 to cause the deformity parameters to be recalculated based on the edited values provided by the user, for example by repeating all or any portion of the calculations performed at operation 322.

At operation 334, a graphical representation of the position and orientation of the reference ring and the respective anatomical structure segment to which it is mounted is generated and displayed. The graphical representation of the position and orientation of the reference ring and the respective anatomical structure segment may be displayed using one or more graphical user interfaces of a computing system. For example, as shown in FIG. 10, interface 1000 includes a graphical representation 1050 of the position and orientation of the reference ring and the respective anatomical structure segment. Graphical representation 1050 includes a representation 1031 of the proximal anatomical structure segment, a representation 1033 of the proximal (reference) ring, and a representation 1032 of the distal anatomical structure segment. In some examples, the graphical representation 1050 may be generated based, at least in part, on the positions and orientations of the reference ring and the respective anatomical structure segment determined at operation 322. The graphical representation of the reference ring and the respective anatomical structure segment may, therefore, reflect and/or indicate the positions and orientations of reference ring and the respective anatomical structure segment determined at operation 322. In some examples, when the user edits one or more mounting parameters and selects Save and Update button 1021, the graphical representation 1050 may also be adjusted to reflect the saved edits to the mounting parameters. Graphical representation 1050 may, for example, improve efficiency and reliability by providing the user with a visual confirmation of information entered into interface 1000, for example to allow fast and easy identification of errors or other problems.

At operation 336, one or more treatment plan options are received, for example using one or more graphical user interfaces of a computing system. A treatment plan is a plan for manipulating the fixation apparatus, for example in order to correct the deformity of the first and the second anatomical structure segments. The treatment plan may include, for example, a plan for making gradual adjustments to the positions and orientations of the fixator rings with respect to each other, for example by changing the lengths of the struts of the fixation apparatus. Referring now to FIG. 11, an example treatment plan interface 1100A is shown. The interface 1100A includes controls for selecting, by a user, various treatment plan options. In particular, controls 1101 and/or 1102 allow selecting of a treatment plan start date, control 1103 allows selection of an option to perform axial movement first (e.g., in an initial part of the treatment, such as prior to rotational movement), control 1104 allows selection of an option to indicate a final distance between reference points, control 1105 allows selection of an option to calculate the treatment plan based on a specified duration (e.g., a number of days) for axial movement, control 1106 allows selection of an option to calculate the treatment plan based on a rate of distraction at the reference point (e.g., for example millimeters (mm)/day) for axial movement, control 1108 allows selection of an option to calculate the treatment plan based on a specified duration (e.g., a number of days) for deformity correction, control 1109 allows selection of an option to calculate the treatment plan based on a rate of distraction at the reference point (e.g., for example millimeters (mm)/day) for deformity correction, and control 1107 allows selection of an option to perform two adjustments per day. In some examples, when control 1007 is not selected, a default option of one adjustment per day may be used. In some examples, after selecting desired treatment plan options, the user may select Update Adjustment Plan button 1110 to trigger generation of the treatment plan. Additionally, after initial generation of the treatment plan, the user may also be permitted to adjust the treatment plan options and have the treatment plan re-generated with the adjusted options by re-selecting Update Adjustment Plan button 1110

At operation 338, manipulations to the fixation apparatus for correction of the anatomical structure deformity (i.e., a treatment plan) are determined. The manipulations to the fixation apparatus may include adjustments to the struts of the fixation apparatus, such as adjustments to the sizes and/or lengths of the struts. In some examples, operation 338 may be performed based, at least in part, on the treatment plan options received at operation 336. For example, operation 338 may be performed based, at least in part, on specified start date, on instructions to perform axial movement first (e.g., in an initial part of the treatment, such as prior to rotational movement), a specified final distance between reference points, instructions to perform additional lengthening by a specified amount, instructions to generate an axial gap to ensure anatomical structure clearance, a specified duration (e.g., a number of days) of treatment, a specified rate of distraction, and/or instructions to perform two perform a specified quantity (e.g., one, two, etc.) of adjustments per day.

In some examples, the treatment plan may also be determined based, at least in part, on a determination of desired changes to the positions and/or orientations of the anatomical structure segments 102, 104, for instance how the anatomical structure segments 102, 104 can be repositioned with respect to each other in order to promote union between the anatomical structure segments 102, 104. For example, in some cases, it may be desirable to change the angulation of the second anatomical structure segment 104 such that the axes L1 and L2 are brought into alignment, and to change the position of the second anatomical structure segment such that the fractured ends 103, 105 of the anatomical structure segments 102, 104 abut each other. Once the desired changes to the positions and/or orientations of the anatomical structure segments 102, 104 have been determined, a treatment plan for effecting the position and/or orientation changes can be determined. In a preferred embodiment, the desired changes to the positions and/or orientations of the anatomical structure segments 102, 104 can be effected gradually, in a series of smaller changes. The positions and/or orientations of the anatomical structure segments 102, 104 can be changed by changing the positions and/or orientations of the upper and lower fixator rings 106, 108 with respect to each other, for instance by lengthening or shortening one or more of the length adjustable struts 116.

The required changes to the geometry of the fixator 100 (i.e., the position and/or orientation of the fixator 100) that can enable the desired changes to the positions and/or orientations of the anatomical structure segments 102, 104 can be computed using the matrix algebra described above. For example, the required repositioning and/or reorientation of the second anatomical structure segment 104 with respect to the first anatomical structure segment 102 can be translated to changes in the position and/or orientation of the lower fixator ring 108 with respect to the upper fixator ring 106.

At operation 340, indications of the determined manipulations to the fixation apparatus are provided to one or more users. For example, in some cases, indications of the determined manipulations to the fixation apparatus may be provided using one or more graphical user interfaces of a computing system, using a printed hard copy, using audio feedback, and/or using other techniques. In particular, referring now to FIG. 12, it is seen that indications of the determined manipulations to the fixation apparatus may be provided within interface 1100B. Specifically, selection of Strut Adjustment Plan tab 1122 may cause treatment plan interface 1100B to provide a chart 1130, including day-by-day manipulation information for each strut within the fixation apparatus. In this example, chart 1130 shows a length for each strut on each day of treatment. In some examples, one or more alerts may be generated for one or more manipulations to the fixation apparatus that result in at least one of strut movement of more than a threshold amount. For example, in some cases, strut movements exceeding particular threshold amount (e.g., 3 mm per day), which may be referred to as rapid strut movements, may be indicated by displaying a red triangle icon next to the indication of the strut movement in chart 1130. As also shown in FIG. 12, a PDF version of the chart 1130 may be generated by selecting View Draft PDF button 1131. The generated PDF may, in some examples, be printed to create a hard copy version of chart 1130.

In the example of FIG. 12, chart 1130 includes blocks 1132-A and 1132-B indicating ranges of dates on which changes of strut sizes, referred to as strut swaps, may be performed. In particular, block 1132-A indicates that a strut swap may be performed for Strut 4 on Day 0 through Day 2, while block 1132-B indicates that a strut swap may be performed for Strut 4 on Day 3 through Day 14 (and subsequent days). In some examples, blocks 1132-A and 1132-B may be color-coded to match a color assigned to a respective strut. For example, blocks 1132-A and 1132-B may be colored green to match a green color that may be assigned to Strut 4. Referring now to FIG. 13, Strut Swaps Calendar tab 1123 of treatment plan interface 1100-C may be selected to generate a calendar 1140 indicating ranges of dates on which strut swaps may be performed.

In some examples, the struts of the fixation apparatus attached to the patient may be color-coded, for example using color-coded caps, marker, or other color-coded materials included within and/or attached to the struts. In some examples, the physical color-coding of the struts in the fixation apparatus attached to the patient may match the color-coding of struts used in the software. For example, the physical color-coding of the struts in the fixation apparatus may match the color-coding of struts that may be used to color-code the blocks 1132-A and 1132-B of chart 1130, graphical representation 520, and other color-coded representations of the struts displayed by the software. In some examples, this may make it easier for physicians and/or patients to confirm that, when they physically adjust a strut on the fixation apparatus, they are adjusting the correct strut by the correct amount.

At operation 342, one or more graphical representations of the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus is generated and displayed. The graphical representation of the position and orientation of the first and the second anatomical structure segments and the rings of the fixation apparatus may be displayed using one or more graphical user interfaces of a computing system. For example, referring back to FIG. 11, selection of Treatment Simulation tab 1121 may cause interface 1100 to display a graphical representation 1150 of the position and orientation of the first and the second anatomical structure segments and the rings of the fixation apparatus. Graphical representation 1150 includes a representation 1031 of the proximal anatomical structure segment, a representation 1033 of the proximal (reference) ring, a representation 1032 of the distal anatomical structure segment, and a representation 1034 of the distal ring. In some examples, the one or more graphical representations of the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus may include day-by-day graphical representations of the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus throughout treatment for the anatomical structure deformity. For example, as shown in FIG. 11, a user may select a particular day of treatment for which to generate and display a graphical representation 1150 using controls 1151, 1152, 1153, and/or 1154. For example, control 1151 may be selected to allow incrementing of the selected day, control 1154 may be selected to allow decrementing of the selected day, and slider 1152 may be slid along bar 1153 to increment and/or decrement the selected day. It is also noted that slider 1152 displays an indication of the currently selected day, which, in the example of FIG. 11, is treatment day zero. Thus, in FIG. 11, graphical representation 1150 shows the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus at treatment day zero. Using controls 1151-1154 to select a different day of treatment may cause graphical representation 1150 to be adjusted to show the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus on the selected different day. As should be appreciated, allowing the surgeon and/or patient to see graphical representations of the position and orientation of the first and second anatomical structure segments and the rings of the fixation apparatus throughout treatment may be beneficial by, for example, providing an additional visual tool to improve accuracy and assist in planning of treatment. Additionally, graphical representation 1150 (as well as graphical representations described herein) may, for example, improve efficiency and reliability by providing the user with a visual confirmation of information entered into interface 1100, for example to allow fast and easy identification of errors or other problems. It is further noted that the view of graphical representation 1150 (as well as other graphical representations described herein) may be rotated (for example by a complete 360 degrees), zoomed in and out, moved in direction, and otherwise manipulated, for example using controls 1181-1184 adjacent to the upper right side of the graphical representation 1150. This may allow views of the first and second anatomical structure segments and/or the rings of the fixation apparatus from various orientations that may not be available, or may be difficult to obtain, using x-rays and other imaging techniques, thereby also improving reliability and accuracy and providing additional visual confirmation of calculated values. In particular, view of the graphical representation 1150 may be rotated using control 1181, zoomed in using control 1182, zoomed out using control 1183, and panned using control 1184. Also, in some examples, other controls, such as a mouse and touchscreen, may also be employed to rotate, zoom, pan, and otherwise manipulate graphical representation 1150. Additionally, in some examples, control 1185 may be used to select an anteroposterior (AP) view, control 1186 may be used to select a lateral view, and control 1187 may be used to select a proximal view.

At operation 344, the treatment plan may be implemented, that is the geometry of the fixation apparatus may be changed, for example based on the manipulations determined at operation 338, in order to change positions and orientations of the anatomical structure segments.

Guided Frame Matching with Graphical Fixator Projection

As described above, a frame matching process may be employed to determine positions and orientations of anatomical structure segments in three-dimensional space, such as for generating a treatment plan for correction of an anatomical deformity. As also described above, in some examples, as part of the frame matching process, a surgeon or other user may identify locations of fixator elements (e.g., rings, struts, etc.) within displayed images (e.g., x-rays) that show the fixator attached to the anatomical structure segments. Some examples of this process are described above with reference to operation 318 of FIG. 3A and FIG. 6. For example, as shown in FIG. 6 and described above, a user may identify locations of struts within AP View image 601-A and LAT View image 601-B as part of the frame matching process. However, it may often be difficult for the user to identify and mark positions of certain fixator elements, such as struts, within the images. In particular, depending upon the location and orientation from which an image is captured, struts and other fixator elements may be not be identified easily, such as because they may wholly or partially overlap one another or may otherwise be obscured within the images. For example, in some cases, it may often be more difficult to identify struts within a lateral image than to identify the struts within an anterior image, such as because the struts may often overlap one another when viewed within the lateral image. For example, as shown in FIG. 6, several of the struts are positioned within LAT View image 601-B such that they are displayed very close together. Specifically, Strut 1 and Strut 2 are displayed very close together on the left side of the image 601-B, Strut 3 and Strut 6 are displayed very close together in the middle side of the image 601-B, and Strut 4 and Strut 5 are displayed very close together on the right side of the image 601-B. This may make it cumbersome for the user to identify, for example, Strut 1 as opposed to Strut 2, Strut 3 as opposed to Strut 6, or Strut 4 as opposed to Strut 5.

In some examples, to alleviate the above and other problems, a guided frame matching technique may be employed. Some examples of the guided frame matching technique will now be described with reference to FIGS. 14-17. Specifically, referring now to FIG. 14, an example process for providing a graphical projection of a fixator using a guided frame matching technique will now be described in detail. As described above, the fixator may include fixator elements such as rings and struts and may be for correcting a deformity of first and second anatomical structure segments. The process of FIG. 14 is initiated at operation 1410, at which first and second images of the first and the second anatomical structure segments and the fixator attached thereto are displayed. The first and the second images may have respective image planes. As shown in FIG. 2 and described above, there is an angle α between the image planes of the images 126, 128.

A first example of the display of the first and the second images at operation 1410 is shown in FIG. 6, which includes AP View image 601-A and LAT View image 601-B as described above. An additional example of the display of the first and the second images at operation 1410 is shown in FIG. 15A, which will now be described in detail. In particular, FIG. 15A displays an AP View image 1501-A and a LAT View image 1501-B, which are images of a fixator 1510 including proximal fixator ring 1511, distal fixator ring 1512 and fixator struts 1513. The images 1501-A and 1501-B show the fixator 1510 attached to a first anatomical structure segment 1521 and a second anatomical structure segment 1522. The first and second images of the first and the second anatomical structure segments and the fixator attached thereto may be displayed at operation 1410 using one or more graphical user interfaces of a computing system. For example, images 1501-A and 1501-B of FIGS. 15A-17B may be displayed using one or more graphical user interfaces of a computing system. It is noted that any, or all, of the contents shown in each of FIGS. 15A-17B may be displayed using one or more graphical user interfaces of a computing system.

It is noted that, in the examples of FIGS. 15A-17B, the images 1501-A and 1501-B are simulated images-as opposed to actual x-rays (as in FIG. 6) or other images captured from an imager or imaging source. It is noted that the simulated images of FIGS. 15-17 are provided merely for ease of illustration of the concepts described herein. In practice, the images 1501-A and 1501-B may be non-simulated images, such as x-rays, which are captured using an imager, imaging source, x-ray imager, camera or other image capture device, and that show an actual fixator that is physically attached to an actual anatomical structure segment (such as shown in FIG. 6). Thus, even though images 1501-A and 1501-B are displayed as simulations, the concepts described herein should be understood to also be applicable to non-simulated images (i.e., images that were captured using an imager, imaging source, x-ray imager, camera or other image capture device) similar to the images 601-A and 601-B of FIG. 6.

At operation 1412, first indications are received of first locations, within the first image, of a plurality of elements of the fixator, such as struts of the fixator, for example using the one or more graphical user interfaces of the computing system. For example, as described above with respect to FIG. 6, the user may indicate locations of struts within the AP View image 601-A, such as by clicking on endpoints of the struts (e.g., hinges) using an attached mouse or other input device. As described above, the strut indicator button 611-A for Strut 1 may be pre-selected automatically for the user. Upon selection (or automatic pre-selection) of the strut indicator button 611-A for Strut 1, the user may proceed to draw (or otherwise indicate) a representation of Strut 1 within AP View image 601-A. For example, in some cases, the user may use a mouse or other input device to select a location 621 (e.g., a center point) of a proximal hinge for Strut 1 within image 601-A. In some examples, the user may then use a mouse or other input device to select a location 622 (e.g., a center point) of the distal hinge of Strut 1 within image 601-A. In some examples, the user may indicate the location and/or length of Strut 1 by selecting the locations of the proximal and distal hinges and/or as the endpoints of a line or vector that represents the location and/or length of Strut 1. For example, as shown in FIG. 6, the software may generate points or circles at the locations 621 and 622 of the proximal and distal hinges selected by the user within image 601-A. Additionally, the software may generate a line 623 representing the location and/or length of Strut 1 that connects the points or circles at the locations 621 and 622 and of the proximal and distal hinges selected by the user within image 601-A. Any other appropriate input techniques may also be employed by the user to indicate a location and/or length of Strut 1 within image 610-A, such as generating line 623 by dragging and dropping a mouse, using a finger and/or pen on a touch screen, keyboard, and others. In some examples, the above described process may be repeated to draw points representing proximal and distal hinges and lines representing the locations and/or lengths of each of the six struts in the AP View image 601-A. A similar technique may also be employed to indicate the locations of each of the six fixator struts 1513 in AP View image 1501-A of FIG. 15A.

In some examples, after the user indicates locations of the struts 1513 within the AP View image 1501-A, the software may use the indicated strut locations to determine locations of the fixator rings 1511 and 1512 within the AP View image 1501-A. The software may then generate ring graphical representations 1531 and 1532, corresponding to the fixator rings 1511 and 1512, respectively, and display the ring graphical representations 1531 and 1532 at the determined locations of the fixator rings 1511 and 1512 within the AP View image 1501-A. Referring now to FIG. 15B, it is seen that ring graphical representations 1531 and 1532 are generated by the software and displayed within AP View image 1501-A at the corresponding locations of the respective fixator rings 1511 and 1512. It is noted that the fixator ring graphical representations 1531 and 1532 are shown in FIG. 15B with a different shade/color than the actual fixator rings 1511 and 1512 to indicate that the fixator ring graphical representations 1531 and 1532 are generated by the software and are not included in the actual underlying AP View image 1501-A. Specifically, the fixator ring graphical representations 1531 and 1532 are shown in blue color/shades, while the fixator rings 1511 and 1512 are shown in black color/shades. The presence of the fixator ring graphical representations 1531 and 1532 in the AP View image 1501-A of FIG. 15B (but not in the LAT View image 1501-B of FIG. 15B) indicates that fixator element location information has been received for the AP View image 1501-A of FIG. 15B but has not yet been received for the LAT View image 1501-B of FIG. 15B.

At operation 1414, a graphical projection of the fixator is overlaid, for example using the one or more graphical user interfaces of the computing system, on the second image. The graphical projection of the fixator may include, for example, graphical representations of the rings and/or the struts of the fixator. For example, referring now to FIG. 16, it is seen that a graphical projection 1600 of the fixator is displayed that includes a graphical representation 1611 of the proximal ring and a graphical representation 1612 of the distal ring. As shown, the graphical projection 1600, including graphical representations 1611 and 1612 is overlaid on the second image, which in this example is the LAT View image 1501-B. Although not shown in FIG. 16, in addition or as an alternative to graphical representations 1611 and 1612 of the fixator rings, the graphical projection 1600 may also include graphical representations of other fixator elements, such as fixator struts. Moreover, in some examples, the graphical representations of the fixator struts included in a graphical projection may be color coded such that different struts are shown in different colors, for example to match different colors of strut indicator buttons 611-A and 611-B.

The graphical projection 1600 of the fixator may be rotated relative to the first locations of the plurality of fixator elements identified in the first image. Specifically, the graphical projection 1600 of the fixator may be rotated relative to the first locations based at least in part on an angle (such as at the exact angle or at an approximation of the angle) of image planes of the first and the second images with respect to one another. As shown in FIG. 2 and described above, there is an angle α between the image planes of the images 126, 128. Thus, in the example of FIG. 16, the AP View image 1501-A may have a respective AP View image plane, and the LAT View image 1501-B may have a respective LAT View image plane at an angle of ninety degrees with respect to the AP View image plane. Accordingly, in the example of FIG. 16, the graphical projection 1600 of the fixator is rotated ninety degrees relative to the first locations of the plurality of fixator elements identified in the first image. For example, both the proximal ring graphical representation 1611 and the distal ring graphical representation 1612 of FIG. 16 are rotated ninety degrees relative to the proximal fixator ring 1511 (and/or the respective ring representation 1531) and distal fixator ring 1512 (and/or the respective ring representation 1532) in the AP View image 1501-A.

The graphical projection 1600 of the fixator may be rotated based at least in part on the angle between image planes of the images because that rotation may correspond to the expected position of the fixator in the second image. For example, if an image plane of the LAT View image 1501-B is at an angle of ninety degrees to an image plane of the AP View image 1501-A, then it may be expected that the locations of the fixator rings in the LAT View image 1501-B will be rotated ninety degrees relative to the locations of the fixator rings in the AP View image 1501-A. In this way, the overlaying of the graphical projection 1600 on the second image may assist the user in identifying locations of the plurality of fixator elements in the second image. In some examples, a user may provide a numerical value, such as a quantity of degrees (e.g., ninety degrees), that expressly indicates to the software the value of the angle between image planes of the images. In other examples, the value of the angle may be inferred by the software based on descriptions of the images (e.g., anteroposterior, anterior, posterior, lateral, medial, etc.) or using other techniques. In the examples of FIGS. 15-17, image 1501-A is an AP View image and image 1501-B is a lateral image. It is noted, however, that the guided frame matching techniques described herein may be used between any different combinations of images taken from any directions and orientations and having image planes at any angle with respect to one another.

Additionally, it is noted that the software may also manipulate other features of the graphical projection 1600 (e.g. size, location, orientations, etc.) such as to correct for other differences (e.g., location, orientation, zoom level, etc.) between the first and the second images. For example, in some cases, if the second image was captured from a closer location to the fixator and/or is more zoomed-in than the first image, then the software may correct for this by enlarging the size of the graphical projection 1600 relative to the size of the fixator elements in the first image. By contrast, in some cases, if the second image was captured from a further location from the fixator and/or is more zoomed-out than the first image, then the software may correct for this by reducing the size of the graphical projection 1600 relative to the size of the fixator elements in the first image.

Thus, in some examples, the graphical projection 1600 of the fixator may be generated based, at least in part, on the first locations of the plurality of fixator elements in the first image indicated at operation 1412. Additionally or alternatively, in some examples, the graphical projection 1600 of the fixator may be generated based, at least in part, on configuration information for the fixator that is provided to the software by the user, such as ring types (e.g., full ring, foot plate, etc.), ring sizes, strut lengths, indications of mounting points (e.g., ring holes), and other information. Various types of configuration information and techniques for providing such information to the software are described in detail above, such as with respect to FIG. 5 and operation 314 of FIG. 3A, and are not repeated here.

At operation 1416, the software may allow a user to manipulate (e.g., resize, rotate, move, etc.) the graphical projection and/or the second image. For example, the user may manipulate the graphical projection to make it more precisely align with the positions of the fixator elements in the second image. For example, the software may provide controls that allow resizing (making the graphical projection larger or smaller) or rotating of the graphical projection relative to its initial placement by the software when being overlaid upon the second image at operation 1414. For example, in some cases, it may be necessary to resize and/or rotate the graphical projection to correct for slight differences in the actual angle between the first and the second images relative to the expected angle (e.g., if the images are actually at an angle of ninety-two degrees rather than ninety degrees, etc.), to correct for differences in distance, position or orientation of the first and the second images relative to the objects included in the images, or for other reasons. In some examples, the software may provide various controls, such as buttons, that allow selections of operations such as move, resize and rotate, and the software may be configured to receive input from input devices, such as a mouse or keyboard, to accomplish those manipulations, for example via drag-and-drop, button clicks, keystrokes, etc.

In some examples, in addition or as an alternative to allowing a user to manipulate the graphical projection, the software may allow the user to manipulate the second image (e.g., LAT View image 1501-B) upon which the graphical projection is overlaid. For example, in some cases, the software may allow the user to resize, rotate and/or move the second image and/or elements shown within the second image, such as to assist in aligning the fixator elements shown in the second image with corresponding elements of the graphical projection. Referring now to FIG. 17A, it is seen that the user has manipulated the second image, which is LAT View image 1501-B, by moving the LAT View image 1501-B down and to the right from its prior screen/interface location shown in FIG. 16. By moving the LAT View image 1501-B in this manner (without moving the graphical projection 1600), this allows the fixator elements in the LAT View image1501-B to be moved down and to the right such that they align with corresponding elements of graphical projection 1600. For example, as shown in FIG. 17A, the graphical representations 1611 and 1612 of the fixator rings substantially align with the respective fixator rings 1511 and 1512. Thus, only small portions of the fixator rings 1511 and 1512 are visible in FIG. 17 because they have been almost entirely overlaid by the respective graphical representations 1611 and 1612 of the fixator rings. In particular, in FIG. 17A, proximal ring graphical representation 1611 substantially aligns with (and almost entirely overlays) proximal fixator ring 1511, and distal ring graphical representation 1612 substantially aligns with (and almost entirely overlays) distal fixator ring 1512.

At operation 1418, second indications are received of second locations, within the second image, of the plurality of elements of the fixator, for example using the one or more graphical user interfaces of the computing system. For example, in some cases, once the graphical projection 1600 of the fixator has been satisfactorily aligned with the position of the fixator in the second image (e.g., in the LAT View image 1501-B), the user may employ the graphical projection 1600 as a guide to assist in identifying the locations of the plurality of fixator elements in the second image (e.g., in the LAT View image 1501-B). For example, although not shown in FIGS. 16 and 17A, the graphical projection 1600 of the fixator may include graphical representations of the fixator struts. In these examples, when the user aligns the graphical projection of the fixator with the position of the fixator in the second image, the graphical representations of the fixator struts in the graphical projection will align with (and overlay) the respective locations of the fixator struts within the second image. As also noted above, graphical representations of the fixator struts in the graphical projection may be color coded such that different struts are shown in different colors, for example to match different colors of strut indicator buttons 611-A and 611-B and different colors of struts in the first image. The color coding of the graphical representations of the struts in the graphical projection may therefore assist the user in distinguishing between respective struts that are positioned closely together in the second image. For example, as shown in FIG. 17A, a first strut 1513-A and a second strut 1513-B are positioned closely together on the right side of the LAT View image 1501-B. If graphical representations of these struts are included in the graphical projection 1600 and are aligned with (and overlaying) the struts 1513-A and 1513-B, then this may assist the user in distinguishing between the struts 1513-A and 1513-B in the LAT View image, particularly if the graphical representations of the struts in the graphical projection 1600 are color coded. For example, if a graphical representation of the first strut 1513-A is shown in red, then the user may immediately appreciate that the red colored strut representation is aligned with and overlaying the first strut 1513-A. Additionally, if a graphical representation of the second strut 1513-B is shown in orange, then the user may immediately appreciate that the orange colored strut representation is aligned with and overlaying the second strut 1513-B. In the manner, the user may employ graphical representations of the struts (and/or other fixator elements) in the graphical projection as a guide to identify respective ones of the plurality of fixator elements in the second image. It is noted that, in addition to the struts, graphical representations 1611 and 1612 of the rings may also be color coded.

Accordingly, by using the graphical projection 1600 of the fixator as a guide, the user may identify locations of the plurality of the fixator elements in the second image. The user may then indicate the locations of these fixator elements to the software, such as by using the same or a similar process as was used to identify the plurality of fixator elements in the first image at operation 1412. For example, the techniques described above in operation 1412 (e.g., identifying proximal and distal hinges or endpoints of each strut) for the first image (AP View images 601-A and 1501-A) may be repeated for the second image (LAT View images 601-B and 1501-B), such as by using LAT View strut indicator buttons 611-B to draw points representing proximal and distal hinges and lines representing the locations and/or lengths of each of the six struts in the LAT View images 601-B and 1501-B.

In some examples, after the user has indicated locations of the struts 1513 and/or other fixator elements within the LAT View image 1501-A at operation 1418 (e.g., using the graphical projection 1600 of the fixator as a guide), the software may use the indicated fixator element locations to determine locations of the fixator rings 1511 and 1512 within the LAT View image 1501-B. The software may then generate ring graphical representations 1731 and 1732, corresponding to the fixator rings 1511 and 1512, respectively, and display the ring graphical representations 1731 and 1732 at the determined locations of the fixator rings 1511 and 1512 within the LAT View image 1501-B. Referring now to FIG. 17B, it is seen that ring graphical representations 1731 and 1732 are generated by the software and displayed within LAT View image 1501-B at the corresponding locations of the respective fixator rings 1511 and 1512.

At operation 1420, the first locations of the plurality of fixator elements in the first image (indicated at operation 1412) and the second locations of the plurality of fixator elements in the second image (indicated at operation 1418 using the graphical projection as a guide) are used to determine positions and orientations of the first and second anatomical structure segments in three-dimensional space. For example, as described in detail above with respect to operation 322 of FIG. 3A, imaging scene parameters may be used to determine positions and orientations of the first and second anatomical structure segments in three-dimensional space. As also described above, the imaging scene parameters may be obtained by comparing the locations of representations of particular components, or fixator elements of the fixator within the two-dimensional spaces of the first and the second images, with the corresponding locations of those same fixator elements in actual, three-dimensional space. As also described above, such as with respect to operation 338 of FIG. 3B, manipulations to the fixation apparatus for correction of the anatomical structure deformity (i.e., a treatment plan) may be determined using the positions and orientations of the first and second anatomical structure segments in three-dimensional space. Specifically, the treatment plan may be determined based, at least in part, on a determination of desired changes to the positions and/or orientations of the anatomical structure segments, for instance how the anatomical structure segments can be repositioned with respect to each other in order to promote union between the anatomical structure segments.

Three-Dimensional Overview of Imaging Scene of the Fixator

Another technique for improving accuracy and reliability of input values and resulting calculations is disclosed herein that provides a three-dimensional overview of an imaging scene of the fixator. The three-dimensional overview may be used to provide feedback and visual confirmation to help ensure that the calculated positions and orientations of anatomical structures is reliable and correct. Various techniques for generating the three-dimensional overview will now be described in detail with reference to FIGS. 18-25. In particular, referring now to FIG. 18 an example process for generating a three-dimensional overview of an imaging scene of a fixator including rings and struts to correct a deformity of first and second anatomical structure segments will now be described in detail. The process of FIG. 18 is initiated at operation 1810, at which first and second images, such as x-rays, of the fixator and the first and the second anatomical structure segments attached thereto are received, for example by a computing system. As described above, the images can be captured using one or more imaging sources, such as x-ray imagers and/or image capturing devices. As also described above, the first and the second images have respective first and second image planes at an angle with respect to one another. The images may be received by a computing system, such as by scanning or otherwise electronically loading or communicating image data for the images to the computing system.

As set forth above, upon receiving the first and second images, frame matching techniques may be employed in association with the first and second images, for example as described above with reference to operations 314-334 of FIGS. 3A-3B, such as to determine positions and orientations of the anatomical structure segments, the fixator, the imaging sources, and other elements of the fixator imaging scene in three-dimensional space. These techniques are described in detail above and are not repeated here. In some examples, upon completion of the frame matching process, for example including operations 314-334 (and optionally the guided frame matching techniques of FIG. 14), a three-dimensional overview may be displayed to the user, such as will now be described in detail. Specifically, at operation 1812 of FIG. 18, a three-dimensional graphical model is displayed, for example using one or more graphical user interfaces of the computing system. The three-dimensional graphical model may include a first image representation that represents the first image and a second image representation that represents the second image. For example, referring now to FIG. 19, it is seen that model 1900, which is a three-dimensional graphical model, includes an AP View image representation 1901-A that represents an AP View image and a LAT View image representation 1901-B that represents a LAT View image. In the example of FIG. 19, the image representations 1901-A and 1901-B are graphical simulations of the first and second images, which may be x-ray images. In some examples, however, the image representations 1901-A and 1901-B may include actual x-ray images or other actual images that are captured from the imaging sources. It is noted that any, or all, of the contents shown in each of FIGS. 19-25 may be displayed using one or more graphical user interfaces of a computing system.

In the model 1900, the image representations 1901-A and 1901-B may be displayed with respect to one another at the same angle as the angle between their respective image planes. For example, the image planes of the AP View image and the LAT View image may have an angle of approximately (but in some cases not exactly) ninety degrees with respect to one another. Thus, in the model 1900, the AP View image representation 1901-A and the LAT View image representation 1901-B are positioned with respect to one another at the same angle as their respective image planes (approximately ninety degrees). In some examples, the software may calculate and display the actual angle between the image planes of the first and the second images as a numerical value.

In some examples, the model 1900 may display graphical representations of respective locations of imaging sources of the first and the second images. In the example of FIG. 19, AP imaging source representation 1911-A represents a location of an imaging source (e.g., x-ray imager, image capture device, etc.) of the AP View image, while LAT imaging source representation 1911-B represents a location of an imaging source (e.g., x-ray imager, image capture device, etc.) of the LAT View image. The imaging source representations 1911-A and 1911-B may indicate respective virtual locations corresponding to the first and the second imaging sources. For example, upon performance of the frame matching process, such as described above with reference to operations 314-334 of FIGS. 3A-3B, the software may be capable of calculating positions and orientations of an entire three-dimensional scene including positions and orientations of the anatomical structure segments, the fixator, and the imaging sources with respect to one another. Thus, based on the frame matching process, the software may determine respective virtual locations corresponding to the first and the second imaging sources. These virtual locations may reflect the distance, positions, and/or orientations of the imaging sources relative to the anatomical structure segments and/or the fixator.

In the example of FIG. 19, a reference location 1913 is shown in both the AP View image representation 1901-A and the LAT View image representation 1901-B. In this particular example, the reference location 1913 is a reference point, such as an endpoint, on a proximal anatomical structure segment 1915.

In some examples, a first virtual line may connect a first virtual location corresponding to the first imaging source to the reference location in the first image representation. In the example of FIG. 19, a beam 1912-A is shown as a graphical representation of this first virtual line that is displayed in the model 1900. As shown, the beam 1912-A connects a first virtual location corresponding to the first imaging source (e.g., the location indicated by AP imaging source representation 1911-A) to the reference location in the first image representation (e.g., the reference location 1913 in the AP View image representation 1901-A).

Also, in some examples, a second virtual line may connect a second virtual location corresponding to the second imaging source to the reference location in the second image representation. In the example of FIG. 19, a beam 1912-B is shown as a graphical representation of this second virtual line that is displayed in the model 1900. As shown, the beam 1912-B connects a second virtual location corresponding to the second imaging source (e.g., the location indicated by LAT imaging source representation 1911-B) to the reference location in the second image representation (e.g., the reference location 1913 in the LAT View image representation 1901-B). Although beams 1912-A and 1912-B are displayed in model 1900, there is no requirement that the first and second virtual lines must be displayed in the model, and some models may not display the beams 1912-A and 1912-B (or may display only portions thereof).

At operation 1814, a first graphical representation associated with a shortest distance (e.g. intersection) between the first virtual line and the second virtual line is displayed in the three-dimensional graphical model. In the example of FIG. 19, beams 912-A and 1912-B intersect, and a point 1914 is shown at an intersection of the beams 1912-A and 1912-B, which is the shortest distance between beams 1912-A and 1912-B. Thus, in this example, the point 1914 is a first graphical representation of the intersection between the first virtual line (represented by beam 1912-A) and the second virtual line (represented by beam 1912-B). In some examples, as opposed to a point, the first graphical representation may simply be an intersection between two graphical lines or beams or may be any other type of graphical representation. The first graphical representation (e.g., point 1914) represents a physical location of the reference location in three-dimensional space. Thus, in the example of FIG. 19, the point 1914 represents a physical location of the endpoint of proximal anatomical structure segment 1915 (which is the reference location 1913) in three-dimensional space.

In the example described above, the beams 1912-A (representing the first virtual line) and 1912-B (representing the second virtual line) intersect one another at the point 1914. In some examples, however, the first and second virtual lines described above may not actually intersect one another. In some examples, in these scenarios, as opposed to being displayed at the intersection point between the lines (since no intersection point exists), the first graphical representation may instead be displayed at a point that bisects (i.e., divides into two equal halves) the shortest distance between the first virtual line and the second virtual line. Specifically, a vector may connect respective points on the first virtual line and the second virtual line at the shortest distance, and the first graphical representation may be displayed at the midpoint of the vector.

Operation 1814 is described above with respect to reference location 1913 on proximal anatomical structure segment 1915. It is noted, however, that operation 1814 may be repeated for any number of other reference locations. For example, FIG. 19 also shows a reference location 1923 in both the AP View image representation 1901-A and the LAT View image representation 1901-B. In this particular example, the reference location 1923 is a reference point, such as an endpoint, on a distal anatomical structure segment 1925. As shown, a beam 1922-A connects a first virtual location corresponding to the first imaging source (e.g., the location indicated by AP imaging source representation 1911-A) to the reference location 1923 in the AP View image representation 1901-A. Additionally, a beam 1922-B connects a second virtual location corresponding to the second imaging source (e.g., the location indicated by LAT imaging source representation 1911-B) to the reference location 1923 in the LAT View image representation 1901-B). Furthermore, a point 1924 is shown at an intersection of the beams 1922-A and 1922-B. Thus, in this example, the point 1924 is a first graphical representation of the intersection between the beam 1922-A and the beam 1922-B. The first graphical representation (e.g., point 1924) represents a physical position of the reference location in three-dimensional space. Thus, in this example, the point 1924 represents a physical location of the endpoint of distal anatomical structure segment 1925 (which is the reference location 1923) in three-dimensional space.

At operation 1816, graphical representations of elements (e.g., rings, struts, etc.) of the fixator may be displayed, in the three-dimensional graphical model, at virtual locations that represent physical locations of the elements of the fixator in the three-dimensional space. For example, referring now to FIG. 20, it is seen that a user may activate a control of the software, such as hexapod visible control 2001, which causes the model 1900 to display graphical representations of the fixator rings. The user may also deactivate the hexapod visible control 2001, which causes the model 1900 to cease to display graphical representations of the fixator rings. As shown in FIG. 20, activation of the hexapod visible control 2001 causes a proximal ring graphical representation 2011 and a distal ring graphical representation 2012 to be displayed in the model 1900. Additionally, referring now to FIG. 21, it is seen that a user may activate a control of the software, such as struts visible control 2101, which causes the model 1900 to display graphical representations 2110 of the fixator struts. The user may also deactivate the struts visible control 2101, which causes the model 1900 to cease to display graphical representations 2110 of the fixator struts. As shown, the graphical representations 2110 of the fixator struts may be color coded, such that different struts are shown in different colors, for example to match different colors of strut indicator buttons 611-A and 611-B of FIG. 6. In some examples, the physical locations of the fixator elements in three-dimensional space may be determined by the software by performing the frame matching techniques described above (e.g., operations 314-334 of FIGS. 3A-3B). The software may then determine virtual locations within the model 1900 that correspond to these physical locations, and the software may display the graphical representations of the fixator elements at the determined virtual locations.

At operation 1818, graphical representations of the first and the second anatomical structure segments may be displayed, in the three-dimensional graphical model, at virtual locations that represent physical locations of the first and the second anatomical structure segments in the three-dimensional space. For example, referring now to FIG. 21, it is seen that a user may activate a control of the software, such as proximal stick visible control 2102, which causes the model 1900 to display a graphical representation 2112 of the proximal anatomical structure segment 1915. The user may also deactivate the proximal stick visible control 2102, which causes the model 1900 to cease to display the graphical representation 2112 of the proximal anatomical structure segment 1915. As also shown in FIG. 21, a user may activate a control of the software, such as distal stick visible control 2103, which causes the model 1900 to display a graphical representation 2113 of the distal anatomical structure segment 1925. The user may also deactivate the distal stick visible control 2103, which causes the model 1900 to cease to display the graphical representation 2113 of the distal anatomical structure segment 1925. In some examples, the physical locations of the anatomical structure segments in three-dimensional space may be determined by the software by performing the frame matching techniques described above (e.g., operations 314-334 of FIGS. 3A-3B). The software may then determine virtual locations within the model 1900 that correspond to these physical locations, and the software may display the graphical representations of the anatomical structure segments at the determined virtual locations.

Thus, as described above, the model 1900 may provide a three-dimensional graphical model that displays the first and the second images (or representations thereof) in combination with graphical representations of imaging sources, graphical representations of reference locations (e.g., endpoints of the first and the second anatomical structure segments), graphical representations of virtual lines connecting virtual locations corresponding to the imaging sources to the reference locations and intersections thereof, graphical representations of the fixator elements (e.g., rings, struts, etc.), and graphical representations of the anatomical structure segments, thereby indicating spatial relationships between these objects. Moreover, each of the graphical representations may be displayed at virtual locations that represent respective physical locations in three-dimensional space. As should be appreciated, the above described three-dimensional graphical model may therefore provide visual feedback that allows the user to locate points and other locations in three-dimensional space and review and confirm the correctness of the values calculated during the frame matching process. For example, the user may confirm that reference locations 1913 and 1923, such as endpoints of the anatomical structure segments, are at correct locations in relation to other objects, such as the fixator rings, fixator struts, and other locations on the anatomical structure segments. For example, in some cases, if the points 1914 and/or 1924 were positioned at an incorrect location relative to the graphical representations 2011 and 2012 of the fixator rings and/or the graphical representations 2110 of the fixator sturts, then this would be an indication to the user that one or more calculations have not been performed correctly, for example due to user error in identifying input values during the frame matching process. For example, if the points 1914 and/or 1924 are positioned at non-sensical locations (e.g., locations that collide with the fixator rings or struts, locations outward from the struts, location above an upper ring or below a lower ring, etc.), then this may be a clear indication of an error in the frame matching calculations. Upon determining such an error, the user may choose to review and resubmit any or all input values provided during the frame matching process and then reperform the calculations.

In some examples, the model 1900 may be zoomable, resizable and rotatable, and otherwise manipulatable by the user. For example, the user may zoom-in to enlarge portions of the model 1900 and/or zoom-out to increase the field of view. As another example, the user may pan and/or rotate the model, such as in any combination of directions (e.g., up, down, left, right, pitch, yaw, etc.). In some examples, the model 1900 may be manipulated to be shown from various different perspectives, such as respective perspectives that correspond to the first and the second images. For example, referring now to FIG. 22, it is seen that a user may select a Show from AP button 2200 to cause the model 1900 to be shown from an AP view perspective corresponding to the AP View image. Additionally, referring now to FIG. 23, it is seen that a user may select a Show from LAT button 2300 to cause the model 1900 to be shown from a LAT view perspective corresponding to the LAT View image. Additionally, referring now to FIG. 24, it is seen that the model 1900 may be rotated vertically relative to the perspectives shown in FIGS. 19-23.

As described above, the first and second images corresponding to image representations 1901-A and 1901-B have image planes at an angle relative to one another. For example, the AP View and LAT View images corresponding to image representations 1901-A and 1901-B may have image planes that are approximately orthogonal to one another. In some cases, however, these image planes may not be exactly orthogonal to one another. In some examples, when the image planes are not exactly orthogonal, the software may display a modified second image representation that is truly orthogonal to the first image representation. The modified second image representation may represent a modified second image having an image plane that is truly orthogonal to the image plane of the first image. For example, referring now to FIG. 25, a modified LAT View image representation 2500 is shown in the model 1900. The modified LAT View image representation 2500 is a modification of LAT View image representation 1901-B. The modified LAT View image representation 2500 is truly orthogonal to the AP View image representation 1901-A within the model 1900. The modified LAT View image representation 2500 may represent a modified LAT View image having an image plane that is truly orthogonal to the image plane of the AP View image. In some examples, a user may activate Ideal Plane Visible control 2510 in order to cause the modified LAT View image representation 2500 to be shown in the model 1900. The user may also deactivate the Ideal Plane Visible control 2510 in order to cause the modified LAT View image representation 2500 to cease to be shown in the model 1900.

In some examples, the software may calculate the angle of the anatomical structure segments that would be displayed in the second image if the second image were truly orthogonal to the first image. The software may then display, in the modified second image representation, a modified second image in which the anatomical structure segments are displayed with the calculated angle with respect to one another. For example, the software may calculate the angle of the anatomical structure segments 1915 and 1925 that would be displayed in the LAT View image if the LAT View image were truly orthogonal to the AP View image. The software may then display, in the modified LAT View image representation 2500, a modified LAT View image in which the anatomical structure segments 1915 and 1925 are displayed with the calculated angle with respect to one another. In some examples, the angles of the anatomical structure segments in the modified LAT View image representation 2500 may be determined based on a knowledge of the positions and orientations of the anatomical structure segments in physical three-dimensional space, such as may be determined by performing the frame matching techniques described above (e.g., operations 314-334 of FIGS. 3A-3B).

As should be appreciated, the ability to generate and display a modified second image representation (e.g., modified LAT View image representation 2500) may provide a number of benefits. For example, when a surgeon measures anatomical structure deformities on two-dimensional images, the assumption is that the images are orthogonal. Any deviation from the orthogonality of these images may lead to an inaccurate measurement, for example associated with angles in an anterior view (varus/valgus) and a lateral view (apex anterior/posterior) beginning to mix. This deviation may result in a residual deformity after the correction. Using frame matching techniques described above, the software has knowledge of the positions and orientations of the anatomical structure segments in physical three-dimensional space. Thus, the software may calculate the angle of the anatomical structure segments that would be displayed in the second image if the second image were truly orthogonal to the first image. In this way, the software may demonstrate to the user how measured anatomical structure deformity values from a second image that is not truly orthogonal to the first image may be adjusted to corrected anatomical structure deformity values that correspond to a modified second image that would be truly orthogonal to the first image and provide a guidance to validate the corrected values for use in the calculations described above. In some examples, the user may be provided with an option to override the corrected values (such as to use the measured values) if the user is not confident with the corrected values.

It is noted that, while the model 1900 described above shows image representations for both the first and second images, a three-dimensional graphical model may also be provided that shows only a single image representation for a single image. Such a single-image model may be useful to provide feedback to the user at an earlier stage of the input process, such as when frame matching has only been performed on a single image, for example when a user has indicated strut locations on the first image but not yet on the second image. Additionally, while the model 1900 described above shows points 1914 and 1924 that represent reference locations of anatomical structures, a three-dimensional graphical model may also be provided that need not necessarily include anatomical structure information. This type of model may also be useful to provide feedback to the user at an earlier stage of the input process, such as when user has indicated location of fixator elements in the first and/or the second image-but has not yet indicated locations of anatomical structures in the first and/or the second image.

For example, for scenarios in which a user has indicated strut locations on a first image (but not yet for the second image) a single-image model could depict an image representation of the first image, an imaging source representation for the first image, and graphical representations of the frame (e.g., the rings and struts). Additionally, if the user subsequently performs deformity planning and indicates the locations of the anatomical structure segments on the first image, then the single-image model could be updated to show planning elements (e.g., anatomical structure reference points, anatomical structure center lines) on the first image representation and to include beams that connect the imaging source representation for the first image to corresponding points on the first image representation, in this way showing the user where they pass the fixator frame. Moreover, for scenarios in which identification of fixator element (e.g. strut) locations has been performed for both images but deformity planning (e.g., indication of anatomical structure locations) has not yet been performed, a model may be generated that shows image representations of the both images, imaging source representations for both images, and graphical representations of the frame (e.g., the rings and struts), thereby allowing the user to review the relative orientation between the images (i.e. angulation and rotation). Any or all of the above described models may be rotated, zoomed and panned by the user similar to the model 1900.

Changing of Distraction Rate

In some examples, during a course of a computer assisted ring fixator treatment, a surgeon may desire a distraction rate change for a patient. This could be due to premature consolidation (correction is too slow), poor regenerate formation (correction is too fast), a strut swap at the clinic needing to be rescheduled, too much pain, or any other reason. In some examples, in order to allow distraction rate to be changed in an efficient and reliable manner, an option may be provided within the software for a surgeon to select a “change distraction rate” button or other control that will allow the distraction rate to be changed to a new distraction rate starting at a given day of the treatment plan and using the new distraction rate for the remainder of the treatment plan. In some examples, this may allow the distraction rate to be changed during the course of treatment (e.g., during an intermediate day within the treatment plan) using only one screen, one field, and one click to produce a clinically relevant change to the patient treatment and potentially reduce the patient time in the frame. In some examples, when the change distraction rate control is selected, the plan may be reopened by the software in a planning state, such as on a treatment plan tab. In some examples, all other tabs (other than the treatment plan tab) may be inactive. The user may then be able to edit either a “Number of Days” field (or other field that represents the treatment plan duration) or a “Distraction at Reference Point” field. The user may then select an “Update Adjustment Plan” control, and the software may generate a new treatment plan starting with the parameters from the day at which the change distraction rate control was selected. The user may then deliver the new plan to patient.

Example Computing Device

Referring to FIG. 26, a suitable computing device such as example computing device 78 can be configured to perform any or all of the techniques set forth above. It will be understood that the computing device 78 can include any appropriate device, examples of which include a desktop computing device, a server computing device, or a portable computing device, such as a laptop, tablet, or smart phone.

In an example configuration, the computing device 78 includes a processing portion 80, a memory portion 82, an input/output portion 84, and a user interface (UI) portion 86. It is emphasized that the block diagram depiction of the computing device 78 is exemplary and not intended to imply a specific implementation and/or configuration. The processing portion 80, memory portion 82, input/output portion 84, and user interface portion 86 can be coupled together to allow communications therebetween. As should be appreciated, any of the above components may be distributed across one or more separate devices and/or locations.

In various embodiments, the input/output portion 84 includes a receiver of the computing device 78, a transmitter of the computing device 78, or a combination thereof. The input/output portion 84 is capable of receiving and/or providing information pertaining to communicate a network such as, for example, the Internet. As should be appreciated, transmit and receive functionality may also be provided by one or more devices external to the computing device 78.

The processing portion 80 may include one or more processors. Depending upon the exact configuration and type of processor, the memory portion 82 can be volatile (such as some types of RAM), non-volatile (such as ROM, flash memory, etc.), or a combination thereof. The computing device 78 can include additional storage (e.g., removable storage and/or non-removable storage) including, but not limited to, tape, flash memory, smart cards, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, universal serial bus (USB) compatible memory, or any other medium which can be used to store information and which can be accessed by the computing device 78.

The computing device 78 also can contain the user interface portion 86 allowing a user to communicate with the computing device 78. The user interface 86 can include inputs that provide the ability to control the computing device 78, via, for example, buttons, soft keys, a mouse, voice actuated controls, a touch screen, movement of the computing device 78, visual cues (e.g., moving a hand in front of a camera on the computing device 78), or the like. The user interface portion 86 can provide outputs, including visual information (e.g., via a display), audio information (e.g., via speaker), mechanically (e.g., via a vibrating mechanism), or a combination thereof. In various configurations, the user interface portion 86 can include a display, one or more graphical user interfaces, a touch screen, a keyboard, a mouse, an accelerometer, a motion detector, a speaker, a microphone, a camera, a tilt sensor, or any combination thereof. Thus, a computing system including, for example, one or more computing devices 78 can include a processor, a display coupled to the processor, and a memory in communication with the processor, one or more graphical user interfaces, and various other components. The memory can have stored therein instructions that, upon execution by the processor, cause the computer system to perform operations, such as the operations described above. As used herein, the term computing system can refer to a system that includes one or more computing devices 78. For instance, the computing system can include one or more server computing devices that communicate with one or more client computing devices.

While example embodiments of devices for executing the disclosed techniques are described herein, the underlying concepts can be applied to any computing device, processor, or system capable of communicating and presenting information as described herein. The various techniques described herein can be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the methods and apparatuses described herein can be implemented, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embodied in tangible non-transitory storage media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium (computer-readable storage medium), wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for performing the techniques described herein. In the case of program code execution on programmable computers, the computing device will generally include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device, for instance a display. The display can be configured to display visual information. The program(s) can be implemented in assembly or machine language, if desired. The language can be a compiled or interpreted language, and combined with hardware implementations.

It should be appreciated that the orthopedic fixation with imagery analysis techniques described herein provide not only for the use of non-orthogonal images, but also allow the use of overlapping images, images captured using different imaging techniques, images captured in different settings, and the like, thereby presenting a surgeon with greater flexibility when compared with existing fixation and imagery techniques.

The techniques described herein also can be practiced via communications embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates to invoke the functionality described herein. Additionally, any storage techniques used in connection with the techniques described herein can invariably be a combination of hardware and software.

While the techniques described herein can be implemented and have been described in connection with the various embodiments of the various figures, it is to be understood that other similar embodiments can be used or modifications and additions can be made to the described embodiments without deviating therefrom. For example, it should be appreciated that the steps disclosed above can be performed in the order set forth above, or in any other order as desired. Further, one skilled in the art will recognize that the techniques described in the present application may apply to any environment, whether wired or wireless, and may be applied to any number of such devices connected via a communications network and interacting across the network. Therefore, the techniques described herein should not be limited to any single embodiment, but rather should be construed in breadth and scope in accordance with the appended claims. 

What is claimed:
 1. A computer-implemented method for providing a graphical projection of a fixator including rings and struts to correct a deformity of first and second anatomical structure segments comprising: displaying, using one or more graphical user interfaces of a computing system, first and second images of the first and the second anatomical structure segments and the fixator attached thereto, the first and the second images having image planes at an angle with respect to one another; receiving, using the one or more graphical user interfaces, first indications of first locations, within the first image, of a plurality of elements of the fixator; overlaying, using the one or more graphical user interfaces, the graphical projection of the fixator on the second image, wherein the graphical projection of the fixator is rotated relative to the first locations based at least in part on the angle; and receiving, using the one or more graphical user interfaces, second indications of second locations, within the second image, of the plurality of elements of the fixator, wherein the graphical projection of the fixator is employable to assist in providing of the second indications.
 2. The computer-implemented method of claim 1, wherein the graphical projection of the fixator is movable, resizable and rotatable by a user.
 3. The computer-implemented method of claim 1, wherein the deformity is corrected using a treatment plan in which the distraction rate is changed during an intermediate day within the treatment plan.
 4. The computer-implemented method of claim 1, wherein the plurality of elements of the fixator include the struts.
 5. The computer-implemented method of claim 1, wherein the graphical projection of the fixator includes graphical representations of the struts.
 6. The computer-implemented method of claim 1, wherein the graphical projection of the fixator includes graphical representations of the rings.
 7. A computer-implemented method for generating a three-dimensional overview of an imaging scene of a fixator including rings and struts to correct a deformity of first and second anatomical structure segments comprising: receiving, by a computing system, first and second images of the fixator and the first and the second anatomical structure segments attached thereto, the first image captured from a first imaging source and the second image captured from a second imaging source, the first and the second images having respective first and second image planes at an angle with respect to one another; displaying, using one or more graphical user interfaces of the computing system, a three-dimensional graphical model that comprises a first image representation that represents the first image and a second image representation that represents the second image, wherein the one or more graphical user interfaces of the computing system display a first virtual line that connects a first virtual location corresponding to the first imaging source to a reference location in the first image representation, and wherein the one or more graphical user interfaces of the computing system display a second virtual line that connects a second virtual location corresponding to the second imaging source to the reference location in the second image representation; and displaying, in the three-dimensional graphical model, a first graphical representation associated with a shortest distance between the first virtual line and the second virtual line, wherein the first graphical representation represents a physical location of the reference location in three-dimensional space.
 8. The computer-implemented method of claim 7, wherein the shortest distance between the first virtual line and the second virtual line is an intersection between the first virtual line and the second virtual line, and wherein the first graphical representation is displayed at the intersection.
 9. The computer-implemented method of claim 7, wherein the first virtual line and the second virtual line do not intersect, and wherein the first graphical representation is displayed at a point that bisects the shortest distance.
 10. The computer-implemented method of claim 7, wherein the reference location is a reference point of the first or the second anatomical structure segment.
 11. The computer-implemented method of claim 7, further comprising displaying, in the three-dimensional graphical model, graphical representations of the rings and the struts of the fixator at virtual locations that represent physical locations of the rings and the struts of the fixator in the three-dimensional space.
 12. The computer-implemented method of claim 7, further comprising displaying, in the three-dimensional graphical model, graphical representations of the first and the second anatomical structure segments at virtual locations that represent physical locations of the first and the second anatomical structure segments in the three-dimensional space.
 13. The computer-implemented method of claim 7, wherein the three-dimensional graphical model displays the first image representation and the second image representation at the angle with respect to one another.
 14. The computer-implemented method of claim 7, further comprising, when the first and the second image planes are non-orthogonal, displaying a modified second image representation that is orthogonal to the first image representation.
 15. The computer-implemented method of claim 7, wherein the three-dimensional graphical model is zoomable and rotatable by a user.
 16. The computer-implemented method of claim 7, further comprising displaying, in the three-dimensional graphical model, graphical representations of the first virtual location corresponding to the first imaging source and the second virtual location corresponding to the second imaging source.
 17. One or more non-transitory computer-readable storage media having stored thereon instructions that, upon execution by one or more computing devices, cause the one or more computing devices to perform operations for generating a three-dimensional overview of an imaging scene of a fixator including rings and struts to correct a deformity of first and second anatomical structure segments comprising: receiving, by a computing system, first and second images of the fixator and the first and the second anatomical structure segments attached thereto, the first image captured from a first imaging source and the second image captured from a second imaging source, the first and the second images having respective first and second image planes at an angle with respect to one another; displaying, using one or more graphical user interfaces of the computing system, a three-dimensional graphical model that comprises a first image representation that represents the first image and a second image representation that represents the second image, wherein the one or more graphical user interfaces of the computing system display a first virtual line that connects a first virtual location corresponding to the first imaging source to a reference location in the first image representation, and wherein the one or more graphical user interfaces of the computing system display a second virtual line that connects a second virtual location corresponding to the second imaging source to the reference location in the second image representation; and displaying, in the three-dimensional graphical model, a first graphical representation associated with a shortest distance between the first virtual line and the second virtual line, wherein the first graphical representation represents a physical location of the reference location in three-dimensional space. 